docs: add Template Library documentation to HSM Templates

docs/4. Product Features/06. HSM Templates.md

@@ -2,9 +2,9 @@
 <h3>
  <table>
   <tr>
-    <td><b>10 minutes read</b></td>
+    <td><b>12 minutes read</b></td>
     <td style={{ paddingLeft: '40px' }}><b>Level: Beginner</b></td>
-    <td style={{ paddingLeft: '40px' }}><b>Last Updated: July 2026</b></td>
+    <td style={{ paddingLeft: '40px' }}><b>Last Updated: August 2026</b></td>
   </tr>
 </table>
 </h3>
@@ -29,6 +29,40 @@ Session Window - A session window refers to the 24-hour period following a user'
 
 ---
 
+## Using the Template Library
+
+**The Template Library is a collection of pre-approved WhatsApp message templates you can use as a starting point instead of writing a new HSM template from scratch.**
+
+Templates in the library are grouped by use case (like appointment reminders, OTPs, and account confirmations) and are already vetted under the `Utility` category, which makes them more likely to get approved quickly. Selecting one pre-fills the create template form - every field stays fully editable before you submit it for approval.
+
+1. Go to the `Templates` page and click on the `Template library` button in the top right corner.
+
+![Templates page with the Template library button](../../static/img/hsm-templates/hsm-templates_library_button.png)
+
+You can also open the library from inside the `Add A New HSM Template` form when creating a new template - look for the same `Template library` button next to `Template Details`.
+
+![Create Template page with the Template library button](../../static/img/hsm-templates/hsm-templates_library_from_create_page.png)
+
+2. The `Template Library` window opens with templates grouped by use case on the left. Use the `Search` box or the language dropdown to narrow the list.
+
+![Template Library modal with use case groups](../../static/img/hsm-templates/hsm-templates_library_modal.png)
+
+3. Click on a use case group to expand it, then select a template to see a live preview of the message on the right, including its variables, footer, and buttons.
+
+![Template Library modal with a template selected and previewed](../../static/img/hsm-templates/hsm-templates_library_preview.png)
+
+4. Click on `Create from template`. This opens the `Add A New HSM Template` form with the language, category, message, footer, and buttons pre-filled from the template.
+
+![Create Template form pre-filled after choosing a template from the library](../../static/img/hsm-templates/hsm-templates_library_prefilled_form.png)
+
+5. Review and edit any field as needed, then follow the steps below in `HSM Template Creation & Approval Submission` to submit it for approval.
+
+:::note
+If you don't see the `Template library` button on your Templates page, ask your Glific admin to enable it for your organization.
+:::
+
+---
+
 ## HSM Template Creation & Approval Submission
 
 1. Login to Glific and click on the `Quick tools-->Templates` option from left panel