diff --git a/jey_erp/custom/sales_invoice_certificates.py b/jey_erp/custom/sales_invoice_certificates.py
new file mode 100644
index 0000000..d4d83e7
--- /dev/null
+++ b/jey_erp/custom/sales_invoice_certificates.py
@@ -0,0 +1,56 @@
+# Sales Invoice multi presented-certificate — server-side foundation.
+#
+# Source of truth for the (possibly multiple) presented certificates of an invoice
+# line is the parent table `custom_item_certificates` (child DocType "Sales Invoice
+# Certificate"), whose rows are linked to an item row by `custom_si_row_key` — the
+# SAME stable row key used by the tax-article multi-select.
+#
+# This validate hook:
+#   1. guarantees every item row has a stable `custom_si_row_key`,
+#   2. drops ONLY orphaned certificate rows (whose parent_row matches no item row),
+#   3. refreshes the `custom_certificates_display` text (the grid cell summary).
+#
+# Certificates are NOT bound to the line's tax template, so — unlike tax articles —
+# the selection is never cleared on template change.
+
+import frappe
+
+
+def sync_item_certificates(doc, method=None):
+    if doc.doctype != "Sales Invoice":
+        return
+
+    # 1) ensure each item row has a unique, stable row key (links it to its certs)
+    seen = set()
+    for item in doc.get("items", []):
+        key = item.get("custom_si_row_key")
+        if not key or key in seen:
+            key = "r" + frappe.generate_hash(length=10)
+            item.custom_si_row_key = key
+        seen.add(key)
+
+    # 2) keep every certificate row that points at a real item row; drop only orphans.
+    item_keys = {item.custom_si_row_key for item in doc.get("items", [])}
+    rows = [
+        r
+        for r in (doc.get("custom_item_certificates") or [])
+        if r.get("parent_row") in item_keys and r.get("certificate")
+    ]
+    doc.custom_item_certificates = rows
+
+    # 3) refresh the per-row "Sertifikatın seriyə / nömrəsi" display label
+    by_row = {}
+    for r in rows:
+        by_row.setdefault(r.parent_row, []).append(r.certificate)
+
+    for item in doc.get("items", []):
+        certs = by_row.get(item.custom_si_row_key, [])
+        if hasattr(item, "custom_certificates_display"):
+            item.custom_certificates_display = _display_label(len(certs))
+
+
+def _display_label(n: int) -> str:
+    """Short summary shown in the grid cell (avoids the Data field length limit)."""
+    if n:
+        return frappe._("{0} selected").format(n)
+    return frappe._("Click to select")
diff --git a/jey_erp/custom_fields.py b/jey_erp/custom_fields.py
index ca57459..48e811a 100644
--- a/jey_erp/custom_fields.py
+++ b/jey_erp/custom_fields.py
@@ -748,6 +748,23 @@ def create_custom_fields():
                 options='Sales Invoice Tax Article',
                 insert_after='custom_item_tax_articles_section'
             ),
+            # Multiple presented certificates per item row, stored on the parent and
+            # linked to each item row by custom_si_row_key (same row-key as the tax
+            # articles above; Frappe has no nested child tables).
+            dict(
+                fieldname='custom_item_certificates_section',
+                label='Item Certificates',
+                fieldtype='Section Break',
+                insert_after='custom_item_tax_articles',
+                collapsible=1
+            ),
+            dict(
+                fieldname='custom_item_certificates',
+                label='Item Certificates',
+                fieldtype='Table',
+                options='Sales Invoice Certificate',
+                insert_after='custom_item_certificates_section'
+            ),
             # New comments section after time_sheet_list
             dict(
                 fieldname='comments_section',
@@ -935,6 +952,18 @@ def create_custom_fields():
                 hidden=0,
                 columns=2,
                 description='Click to select tax articles'
+            ),
+            # --- multi presented-certificate per item row (click the cell to edit) ---
+            dict(
+                fieldname='custom_certificates_display',
+                label='Sertifikatın seriyə / nömrəsi',
+                fieldtype='Data',
+                insert_after='custom_tax_articles_display',
+                read_only=1,
+                in_list_view=1,
+                hidden=0,
+                columns=2,
+                description='Click to select certificates'
             )
         ],
         "Purchase Invoice Item": [
diff --git a/jey_erp/hooks.py b/jey_erp/hooks.py
index 8294e12..2e9193e 100644
--- a/jey_erp/hooks.py
+++ b/jey_erp/hooks.py
@@ -13,6 +13,7 @@ app_include_js = [
     "/assets/jey_erp/js/sales_invoice.js",
     "/assets/jey_erp/js/sales_invoice_vat.js",
     "/assets/jey_erp/js/sales_invoice_tax_articles.js",
+    "/assets/jey_erp/js/sales_invoice_certificates.js",
     "/assets/jey_erp/js/sales_order_vat.js",
     "/assets/jey_erp/js/asset.js",
     "/assets/jey_erp/js/link_field_fix.js",
@@ -59,6 +60,7 @@ doc_events = {
         "validate": [
             "jey_erp.custom.sales_invoice.calculate_tax_free_amounts",
             "jey_erp.custom.sales_invoice_tax_articles.sync_item_tax_articles",
+            "jey_erp.custom.sales_invoice_certificates.sync_item_certificates",
         ],
         "on_update": [
             "jey_erp.custom.sales_invoice.calculate_tax_free_amounts",
diff --git a/jey_erp/jey_erp/doctype/sales_invoice_certificate/__init__.py b/jey_erp/jey_erp/doctype/sales_invoice_certificate/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.json b/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.json
new file mode 100644
index 0000000..21599f1
--- /dev/null
+++ b/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.json
@@ -0,0 +1,40 @@
+{
+ "actions": [],
+ "creation": "2026-06-16 00:00:00.000000",
+ "doctype": "DocType",
+ "editable_grid": 1,
+ "engine": "InnoDB",
+ "field_order": [
+  "parent_row",
+  "certificate"
+ ],
+ "fields": [
+  {
+   "fieldname": "parent_row",
+   "fieldtype": "Data",
+   "in_list_view": 1,
+   "label": "Item Row Key",
+   "read_only": 1
+  },
+  {
+   "fieldname": "certificate",
+   "fieldtype": "Link",
+   "in_list_view": 1,
+   "label": "Certificate",
+   "options": "E-Taxes Presented Certificate",
+   "reqd": 1
+  }
+ ],
+ "index_web_pages_for_search": 1,
+ "istable": 1,
+ "links": [],
+ "modified": "2026-06-16 00:00:00.000000",
+ "modified_by": "Administrator",
+ "module": "Jey Erp",
+ "name": "Sales Invoice Certificate",
+ "owner": "Administrator",
+ "permissions": [],
+ "sort_field": "modified",
+ "sort_order": "DESC",
+ "states": []
+}
diff --git a/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.py b/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.py
new file mode 100644
index 0000000..7a16b8c
--- /dev/null
+++ b/jey_erp/jey_erp/doctype/sales_invoice_certificate/sales_invoice_certificate.py
@@ -0,0 +1,8 @@
+# Copyright (c) 2026, Ali and contributors
+# For license information, please see license.txt
+
+from frappe.model.document import Document
+
+
+class SalesInvoiceCertificate(Document):
+	pass
diff --git a/jey_erp/patches.txt b/jey_erp/patches.txt
index e14350f..8e84eee 100644
--- a/jey_erp/patches.txt
+++ b/jey_erp/patches.txt
@@ -15,4 +15,5 @@ jey_erp.patches.remove_won_lost_checkboxes
 jey_erp.patches.drop_orphan_bank_doctypes
 jey_erp.patches.backfill_si_tax_article_row_keys
 jey_erp.patches.backfill_sales_invoice_tax_articles_history
-jey_erp.patches.add_tax_articles_to_si_grid_views
\ No newline at end of file
+jey_erp.patches.add_tax_articles_to_si_grid_views
+jey_erp.patches.add_certificates_to_si_grid_views
\ No newline at end of file
diff --git a/jey_erp/patches/add_certificates_to_si_grid_views.py b/jey_erp/patches/add_certificates_to_si_grid_views.py
new file mode 100644
index 0000000..267654e
--- /dev/null
+++ b/jey_erp/patches/add_certificates_to_si_grid_views.py
@@ -0,0 +1,53 @@
+import json
+
+import frappe
+
+
+def execute():
+	"""Inject the new "Sertifikatın seriyə / nömrəsi" column into saved Sales Invoice
+	Item grid layouts.
+
+	Per-user grid column layouts live in `__UserSettings` (GridView). A layout saved
+	before this feature does not list `custom_certificates_display`. Frappe renders the
+	saved list verbatim and ignores the new in_list_view field, so the certificate cell
+	never appears for those users until they add it manually via the grid gear.
+
+	Add `custom_certificates_display` to every saved layout that doesn't already have it,
+	positioned right after the tax-articles cell. Purely additive and idempotent.
+	"""
+	rows = frappe.db.sql(
+		"select user, data from `__UserSettings` where doctype = 'Sales Invoice'",
+		as_dict=True,
+	)
+	for r in rows:
+		try:
+			data = json.loads(r.data or "{}")
+		except (ValueError, TypeError):
+			continue
+
+		grid_view = data.get("GridView") or {}
+		cols = grid_view.get("Sales Invoice Item")
+		if not cols:
+			continue
+
+		names = [c.get("fieldname") for c in cols]
+		if "custom_certificates_display" in names:
+			continue
+
+		new_col = {"fieldname": "custom_certificates_display", "columns": 2}
+		if "custom_tax_articles_display" in names:
+			cols.insert(names.index("custom_tax_articles_display") + 1, new_col)
+		elif "item_tax_template" in names:
+			cols.insert(names.index("item_tax_template") + 1, new_col)
+		else:
+			cols.append(new_col)
+
+		grid_view["Sales Invoice Item"] = cols
+		data["GridView"] = grid_view
+		frappe.db.sql(
+			"update `__UserSettings` set data = %s where user = %s and doctype = 'Sales Invoice'",
+			(json.dumps(data), r.user),
+		)
+
+	frappe.db.commit()
+	frappe.cache().delete_value("_user_settings")
diff --git a/jey_erp/public/js/sales_invoice_certificates.js b/jey_erp/public/js/sales_invoice_certificates.js
new file mode 100644
index 0000000..5adfd07
--- /dev/null
+++ b/jey_erp/public/js/sales_invoice_certificates.js
@@ -0,0 +1,184 @@
+// Multiple presented certificates per Sales Invoice Item row.
+// Click the read-only "Sertifikatın seriyə / nömrəsi" cell -> on a row that has no
+// certificate yet, a yes/no question is asked first ("0% dərəcəsi ilə ƏDV-yə cəlb
+// olunma haqqında sertifikatlar var?"). Answering "Hə" opens a dialog with a Table
+// MultiSelect field (a Link control under the hood => native search + Advanced
+// Search) pre-filled with the row's certificates as pills; answering "Yox" closes
+// it without opening anything. Once the row already has certificates, the cell opens
+// the picker directly.
+//
+// Source of truth = parent table `custom_item_certificates`, linked to each item row
+// by `custom_si_row_key` — the SAME row key the tax-article multi-select uses.
+
+const CERT_DIALOG_CLASS = "certificates-dialog";
+const CERT_CHILD_DOCTYPE = "Sales Invoice Certificate";
+const CERT_DISPLAY_FIELD = "custom_certificates_display";
+const CERT_CONFIRM_MSG = "0% dərəcəsi ilə ƏDV-yə cəlb olunma haqqında sertifikatlar var?";
+
+if (!document.getElementById("certmulti-style")) {
+	const style = document.createElement("style");
+	style.id = "certmulti-style";
+	const F = CERT_DISPLAY_FIELD;
+	const D = "." + CERT_DIALOG_CLASS;
+	style.textContent = [
+		// grid cell: clickable, click passes through the read-only input
+		'.grid-row [data-fieldname="' + F + '"]{cursor:pointer;}',
+		'.grid-row [data-fieldname="' + F + '"] input,',
+		'.grid-row [data-fieldname="' + F + '"] textarea,',
+		'.grid-row [data-fieldname="' + F + '"] .like-disabled-input{pointer-events:none;}',
+
+		// keep the dropdown (incl. native "Advanced Search") reachable, not clipped
+		D + " .modal-body," + D + " .frappe-control," + D + " .form-group," +
+			D + " .control-input-wrapper{overflow:visible!important;}",
+		D + " .awesomplete > ul{max-height:260px;overflow-y:auto;z-index:1080;}",
+
+		// ONE seamless surface: keep only the single .modal-content gradient
+		D + " .modal-header," + D + " .modal-body," + D + " .modal-footer," +
+			D + " .form-layout," + D + " .form-page," + D + " .form-section," +
+			D + " .section-body," + D + " .form-column," + D + " .table-multiselect{" +
+			"background:transparent!important;background-image:none!important;" +
+			"box-shadow:none!important;border:none!important;}",
+
+		// thin dividers under the title and above the footer
+		D + " .modal-header{border-bottom:1px solid rgba(0,0,0,.15)!important;}",
+		D + " .modal-footer{border-top:1px solid rgba(0,0,0,.12)!important;}",
+
+		// trim the empty space above the field
+		D + " .modal-body{padding-top:14px!important;}",
+
+		// the search input as its own bordered field, just below the pills
+		D + " .table-multiselect .awesomplete{display:block;width:100%;margin-top:8px;}",
+		D + " .table-multiselect .awesomplete input{display:block;width:100%;" +
+			"border:1px solid var(--border-color,#999)!important;" +
+			"border-radius:var(--border-radius,6px)!important;padding:4px 8px!important;min-height:28px;}",
+	].join("");
+	document.head.appendChild(style);
+}
+
+frappe.ui.form.on("Sales Invoice", {
+	onload(frm) {
+		ensure_cert_setup(frm);
+	},
+	refresh(frm) {
+		ensure_cert_setup(frm);
+	},
+});
+
+function ensure_cert_setup(frm) {
+	if (frm.__certificates_bound) return;
+	frm.__certificates_bound = true;
+
+	$(document)
+		.off("mousedown.certmulti")
+		.on("mousedown.certmulti", '[data-fieldname="' + CERT_DISPLAY_FIELD + '"]', function (ev) {
+			const grid_row = $(this).closest(".grid-row").data("grid_row");
+			const cdn = grid_row && grid_row.doc && grid_row.doc.name;
+			if (cdn && frm.fields_dict.items && frm.fields_dict.items.grid) {
+				ev.stopPropagation();
+				handle_certificate_cell_click(frm, cdn);
+			}
+		});
+}
+
+function handle_certificate_cell_click(frm, cdn) {
+	const row = locals["Sales Invoice Item"][cdn];
+	if (!row) return;
+
+	// Already has certificates on this row -> open the picker straight away.
+	const key = row.custom_si_row_key;
+	const has_certs =
+		key &&
+		(frm.doc.custom_item_certificates || []).some(
+			(r) => r.parent_row === key && r.certificate
+		);
+
+	if (has_certs) {
+		open_certificate_dialog(frm, cdn);
+		return;
+	}
+
+	// First time on this row -> ask whether such certificates exist at all.
+	frappe.confirm(
+		__(CERT_CONFIRM_MSG),
+		() => open_certificate_dialog(frm, cdn), // "Hə" / Yes
+		() => {} // "Yox" / No -> open nothing
+	);
+}
+
+function open_certificate_dialog(frm, cdn) {
+	const row = locals["Sales Invoice Item"][cdn];
+	if (!row) return;
+
+	if (!row.custom_si_row_key) {
+		row.custom_si_row_key = "r" + Math.random().toString(36).slice(2, 12);
+	}
+	const key = row.custom_si_row_key;
+
+	// Table MultiSelect value = array of child-row objects keyed by the link field.
+	const current = (frm.doc.custom_item_certificates || [])
+		.filter((r) => r.parent_row === key && r.certificate)
+		.map((r) => ({ certificate: r.certificate }));
+
+	const d = new frappe.ui.Dialog({
+		title: __("Sertifikatın seriyə / nömrəsi") + " — " + (row.item_code || "#" + row.idx),
+		fields: [
+			{
+				fieldname: "certificates",
+				fieldtype: "Table MultiSelect",
+				label: __("Select certificates"),
+				options: CERT_CHILD_DOCTYPE,
+				get_query() {
+					return frm.doc.company ? { filters: { company: frm.doc.company } } : {};
+				},
+			},
+		],
+		primary_action_label: __("Save"),
+		primary_action(values) {
+			const selected = Array.from(
+				new Set((values.certificates || []).map((r) => r.certificate).filter(Boolean))
+			);
+			frm.doc.custom_item_certificates = (frm.doc.custom_item_certificates || []).filter(
+				(r) => r.parent_row !== key
+			);
+			selected.forEach((c) => {
+				const child = frm.add_child("custom_item_certificates");
+				child.parent_row = key;
+				child.certificate = c;
+			});
+			const display = selected.length
+				? __("{0} selected", [selected.length])
+				: __("Click to select");
+			frappe.model.set_value(row.doctype, row.name, CERT_DISPLAY_FIELD, display);
+			frm.refresh_field("custom_item_certificates");
+			frm.refresh_field("items");
+			d.hide();
+		},
+	});
+
+	d.$wrapper.addClass(CERT_DIALOG_CLASS);
+	d.add_custom_action(__("Clear all"), () => d.set_value("certificates", []));
+
+	// Robust pill removal inside a Dialog (Table MultiSelect's own .btn-remove handler
+	// does not update the field value in a dialog). Intercept in the CAPTURE phase and
+	// rebuild the value as: current minus the clicked certificate.
+	const fld = d.fields_dict.certificates;
+	fld.$wrapper[0].addEventListener(
+		"click",
+		function (e) {
+			const btn = e.target.closest(".btn-remove");
+			if (!btn) return;
+			e.stopPropagation();
+			const pill = btn.closest(".tb-selected-value");
+			const removed = pill ? decodeURIComponent(pill.getAttribute("data-value") || "") : "";
+			const remaining = (fld.get_value() || [])
+				.map((r) => (typeof r === "string" ? r : r && r.certificate))
+				.filter((n) => n && n !== removed)
+				.map((n) => ({ certificate: n }));
+			fld.set_value(remaining);
+		},
+		true
+	);
+
+	d.set_value("certificates", current);
+	d.show();
+}
diff --git a/jey_erp/public/js/sales_invoice_tax_articles.js b/jey_erp/public/js/sales_invoice_tax_articles.js
index 865a343..d549dc2 100644
--- a/jey_erp/public/js/sales_invoice_tax_articles.js
+++ b/jey_erp/public/js/sales_invoice_tax_articles.js
@@ -127,6 +127,24 @@ function open_tax_article_dialog(frm, cdn) {
 	const row = locals["Sales Invoice Item"][cdn];
 	if (!row) return;
 
+	// Tax articles are locked (read-only) for a line that already has a presented
+	// certificate — the certificate determines the 0% treatment for that line.
+	const cert_key = row.custom_si_row_key;
+	const has_cert =
+		cert_key &&
+		(frm.doc.custom_item_certificates || []).some(
+			(r) => r.parent_row === cert_key && r.certificate
+		);
+	if (has_cert) {
+		frappe.show_alert({
+			message: __(
+				"Tax articles are read-only while a certificate is selected for this line. Remove the certificate to edit them."
+			),
+			indicator: "orange",
+		});
+		return;
+	}
+
 	const group = tax_article_group_for(row.item_tax_template);
 	if (!group) {
 		frappe.show_alert({
diff --git a/jey_erp/translation_markers.py b/jey_erp/translation_markers.py
index 3d5051a..93ab6e5 100644
--- a/jey_erp/translation_markers.py
+++ b/jey_erp/translation_markers.py
@@ -41,6 +41,7 @@ _lt("Cash Registers")
 _lt("Chief Executive Officer")
 _lt("Citizenship Country")
 _lt("City (for print formats)")
+_lt("Click to select certificates")
 _lt("Click to select tax articles")
 _lt("Code of the Cadastral Valuation District")
 _lt("Code of the Territorial Unit")
@@ -96,6 +97,7 @@ _lt("Is Sub Account")
 _lt("Is Taxpayer in Cancellation Process")
 _lt("Is taxes document")
 _lt("Item")
+_lt("Item Certificates")
 _lt("Item Tax Articles")
 _lt("Job Applicant")
 _lt("Kassa metodu — gəlir və xərclər yalnız ödəniş zamanı tanınır. ƏDV öhdəliyi yalnız ödəniş alındıqda yaranır.\nHesablama metodu — gəlir və xərclər faktura zamanı tanınır.")
@@ -150,6 +152,7 @@ _lt("Row Key")
 _lt("SSN")
 _lt("Selected customer object from E-Taxes (auto-filled)")
 _lt("Seller")
+_lt("Sertifikatın seriyə / nömrəsi")
 _lt("Settlements")
 _lt("Special Tax Regime")
 _lt("Sport Betting Operator")