[Excel, Word] (UI/UX) Document TaskPaneApi 1.1 requirement set (#2365)

* Draft TaskPaneApi 1.1

* Add supported build number

* Update ms.date

Author: samantharamon

docs/requirement-sets/common/office-add-in-requirement-sets.md

@@ -1,7 +1,7 @@
 ---
 title: Office Common API requirement sets
 description: Learn more about the Office Common API requirement sets.
-ms.date: 03/11/2025
+ms.date: 10/10/2025
 ms.topic: overview
 ms.localizationpriority: medium
 ---
@@ -248,6 +248,14 @@ See [Add-in command requirement sets](add-in-commands-requirement-sets.md).
 
 ---
 
+### TaskPaneApi
+
+| Minimum Office application support | Methods in set |
+|:-----|:-----|
+| See [Task Pane API requirement sets](task-pane-api-requirement-sets.md). | <ul><li>TaskPane.setWidth</li></ul> |
+
+---
+
 ### TextBindings
 
 | Minimum Office application support | Methods in set |

docs/requirement-sets/common/task-pane-api-requirement-sets.md

@@ -0,0 +1,35 @@
+---
+title: Task Pane API requirement sets
+description: Learn more about the Task Pane API requirement sets and the platforms it supports.
+ms.date: 10/10/2025
+ms.topic: overview
+ms.localizationpriority: medium
+---
+
+# Task Pane API requirement sets
+
+Requirement sets are named groups of API members. Office Add-ins use requirement sets specified in the manifest or use a runtime check to determine whether an Office application supports APIs that an add-in needs. For more information, see [Office versions and requirement sets](/office/dev/add-ins/develop/office-versions-and-requirement-sets).
+
+With the Task Pane API requirement set, you can manage the task pane of an add-in. For example, you can change the width of an add-in's task pane.
+
+## Support
+
+`TaskPaneApi 1.1` is available with **Excel** and **Word**. The following table lists the Task Pane API requirement sets, its supported Office client applications, and the minimum builds or versions for those applications, where applicable.
+
+| Requirement set | Office on the web | Office on Windows<ul><li>Microsoft 365 subscription</li><li>retail perpetual</li><li>volume-licensed perpetual</li></ul> | Office on Mac | Office on iOS | Outlook on Android |
+|:-----|:-----|:-----|:-----|:-----|:-----|
+| TaskPaneApi 1.1 | Supported | Version 2507 (Build 19029.20004) | Not supported | Not supported | Not supported |
+
+## Office Common API requirement sets
+
+For information about Common API requirement sets, see [Office Common API requirement sets](office-add-in-requirement-sets.md).
+
+## TaskPaneApi 1.1
+
+For details about the API, see [Office.TaskPane](/javascript/api/office/office.taskpane).
+
+## See also
+
+- [Office versions and requirement sets](/office/dev/add-ins/develop/office-versions-and-requirement-sets)
+- [Specify Office applications and API requirements](/office/dev/add-ins/develop/specify-office-hosts-and-api-requirements)
+- [Office Add-ins manifest](/office/dev/add-ins/develop/add-in-manifests)