[Outlook] (accounts) Clarify add-in support for non-Microsoft mailbox accounts (#5245)

* Draft add-in support on non-Microsoft accounts

* Clarify support on classic Outlook on Windows and add links

* Update ms.date

* Apply suggestions from review

Co-authored-by: Elizabeth Samuel <[email protected]>

---------

Co-authored-by: Elizabeth Samuel <[email protected]>

Author: samantharamon

docs/outlook/one-outlook.md

@@ -1,7 +1,7 @@
 ---
 title: Develop Outlook add-ins for the new Outlook on Windows
 description: Learn how to develop add-ins that are compatible with the new Outlook on Windows.
-ms.date: 06/26/2025
+ms.date: 07/01/2025
 ms.localizationpriority: medium
 ---
 
@@ -64,7 +64,7 @@ Test your Outlook web add-in in the new Outlook on Windows today! To switch to t
 - Have a Microsoft 365 work or school account connected to Exchange Online. The new client doesn't currently support on-premises, hybrid, or sovereign Exchange accounts.
 
     > [!NOTE]
-    > While you can add non-Microsoft mail accounts, such as Gmail, to the new Outlook on Windows, you can only use Outlook add-ins with a Microsoft account.
+    > While you can add non-Microsoft mail accounts, such as Gmail, to the new Outlook on Windows, you can only use Outlook add-ins with a Microsoft account. For more information, see the "Supported accounts" section of the [Outlook add-ins overview](outlook-add-ins-overview.md#supported-accounts).
 
 - Have a minimum OS installation of Windows 10 Version 1809 (Build 17763).
 

docs/outlook/outlook-add-ins-overview.md

@@ -1,7 +1,7 @@
 ---
 title: Outlook add-ins overview
 description: Outlook add-ins extend or customize the Outlook UI and are developed by Microsoft and partners using our web-based platform.
-ms.date: 06/05/2025
+ms.date: 07/01/2025
 ms.topic: overview
 ms.custom: scenarios:getting-started
 ms.localizationpriority: high
@@ -92,6 +92,22 @@ However, add-ins won't activate on IRM-protected items when:
 
 Outlook add-ins are supported in Outlook on the web, Outlook on Windows (new and classic), Outlook on Mac, Outlook on iOS, Outlook on Android, and Outlook.com. Not all of the newest features are supported in all clients at the same time. For details about feature support on clients and servers, see [Requirement sets supported by Exchange servers and Outlook clients](/javascript/api/requirement-sets/outlook/outlook-api-requirement-sets#requirement-sets-supported-by-exchange-servers-and-outlook-clients) and articles specific to those features.
 
+## Supported accounts
+
+On supported Outlook clients, add-ins can run on Outlook.com (consumer or personal) and Microsoft 365 business mailbox accounts. For more information on Microsoft accounts, see [What's the difference between a Microsoft account and a work or school account?](https://support.microsoft.com/account-billing/72f10e1e-cab8-4950-a8da-7c45339575b0).
+
+While non-Microsoft mailbox accounts, such as Gmail and Yahoo Mail, can be added to certain Outlook clients, Outlook add-ins aren't always supported on these accounts. The following table outlines add-in support on non-Microsoft accounts for each Outlook client.
+
+|Outlook client|Add-in support on non-Microsoft accounts|
+|-----|-----|
+|Web|Not supported.|
+|new Outlook on Windows|Not supported.|
+|classic Outlook on Windows|Not supported.|
+|Mac|<ul><li>If a non-Microsoft account was added using the IMAP CloudCache option, add-ins are supported.</li><li>If a non-Microsoft account was added using the IMAP Direct option, add-ins aren't supported.</li></ul>|
+|Mobile (Android and iOS)|Not supported.|
+
+When using non-Microsoft accounts that support add-ins in Outlook, note that you must first select a folder or item in the non-Microsoft mailbox to load the add-in.
+
 ## Get started building Outlook add-ins
 
 To get started building Outlook add-ins, try the following:

docs/outlook/outlook-mobile-addins.md

@@ -1,15 +1,15 @@
 ---
 title: Add-ins for Outlook on mobile devices
 description: Outlook mobile add-ins are supported on all Microsoft 365 business accounts and Outlook.com accounts.
-ms.date: 06/19/2025
+ms.date: 07/01/2025
 ms.localizationpriority: medium
 ---
 
 # Add-ins for Outlook on mobile devices
 
 Add-ins now work in Outlook on mobile devices, using the same APIs available for other Outlook endpoints. If you've built an add-in for Outlook already, it's easy to get it working on Outlook mobile.
 
-Outlook mobile add-ins are supported on all Microsoft 365 business accounts and Outlook.com accounts. However, support is not currently available on Gmail accounts.
+Outlook mobile add-ins are supported on all Microsoft 365 business accounts and Outlook.com accounts. However, support isn't currently available for non-Microsoft accounts, such as Gmail. For more information, see the "Supported accounts" section of [Outlook add-ins overview](outlook-add-ins-overview.md#supported-accounts).
 
 **An example task pane in Outlook on iOS**