How to add a shared mailbox in Office 365 across different platforms

To add a shared mailbox in Office 365 across different platforms, follow the steps outlined below for Outlook on Windows, Mac, and the Web App.

Outlook for Windows:

1. **Automatic Addition:**

   - If your administrator has granted you access to a shared mailbox, it should automatically appear in your Outlook folder pane after you restart Outlook.

2. **Manual Addition:**

   - Click on the **File** tab.

   - Select **Account Settings** > **Account Settings**.

   - Choose your account and click **Change**.

   - Click **More Settings** > **Advanced** tab.

   - Under **Open these additional mailboxes**, click **Add**.

   - Enter the name or email address of the shared mailbox and click **OK**.

   - Click **Apply**, then **OK**, and finally **Next** and **Finish**.

   - Restart Outlook; the shared mailbox should now appear in your folder list.

**Outlook for Mac:**

1. **Using Delegation and Sharing:**

   - Open Outlook and go to **Tools** > **Accounts**.

   - Select your account and click **Delegation and Sharing**.

   - Navigate to the **Shared With Me** tab.

   - Click the **+** button and search for the shared mailbox by name or email address.

   - Select the mailbox and click **Add**.

   - Close the Accounts window; the shared mailbox will appear in your folder list.

**Outlook on the Web:**

1. **Adding a Shared Folder:**

   - Log in to [Outlook on the web](https://outlook.office.com) with your Office 365 credentials.

   - Right-click on **Folders** in the left navigation pane.

   - Select **Add shared folder**.

   - Enter the name or email address of the shared mailbox and click **Add**.

   - The shared mailbox will now appear in your folder list.

**Outlook Mobile App (iOS and Android):**

1. **Adding a Shared Mailbox:**

   - Open the Outlook app and tap the **Home** icon.

   - Tap **Add Account** > **Add a Shared Mailbox**.

   - Enter the email address of the shared mailbox and tap **Continue**.

   - The shared mailbox will appear in your account list within the app.

For more detailed instructions, you can refer to Microsoft's official documentation:

- [Open and use a shared mailbox in Outlook](https://support.microsoft.com/en-us/office/open-and-use-a-shared-mailbox-in-outlook-d94a8e9e-21f1-4240-808b-de9c9c088afd)

- [Open a shared Mail, Calendar, or People folder in Outlook for Mac](https://support.microsoft.com/en-us/office/open-a-shared-mail-calendar-or-people-folder-in-outlook-for-mac-6ecc39c5-5577-4a1d-b18c-bbdc92972cb2)

- [Open and use a shared mailbox in Outlook Web App](https://support.microsoft.com/en-us/office/open-and-use-a-shared-mailbox-in-outlook-web-app-bc127866-42be-4de7-92ae-1ef2f787fd5c)

Ensure you have the necessary permissions to access the shared mailbox. If you encounter any issues, contact your IT administrator for assistance.