Share email mailbox between organizations.

Question

Hello

Please i need your help on this issue.

We are working together with a a sales organisation named ub-xxxxx.de and have to share a mailbox named ver@ga-xxxx.de with one of their employees.

ub-xxxxx.de does also use office 365.

Answer 1

Hi @IniobongNkanga-8038 ,

Welcome to the Microsoft Q&A platform!

According to your description, to share a mailbox in Office 365, you can follow the steps below:

1. Create a shared mailbox:

• Sign in to the Microsoft 365 admin center.
• Go to Teams and groups > Shared mailboxes.
• Click + Add a shared mailbox.
• Enter the name and email of the shared mailbox (for example, ver@ga-xxxx.de).
• Click Save changes.

2. Add members to the shared mailbox:

• After creating the shared mailbox, select it from the list.
• Click Add members.
• Select the people who need to access the shared mailbox and click Add.

3. Access the shared mailbox in Outlook:

• In Outlook, go to the folder pane.
• Right-click your primary mailbox and select Add shared folder.
• Enter the email address of the shared mailbox (for example, ver@ga-xxxx.de) and click Add.

4. Send an email from the shared mailbox:

• When composing a new email, click the From field.
• Select the shared mailbox address from the drop-down list.

These steps should help you set up and share a mailbox with employees from ub-xxxxx.de.

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Please feel free to contact me for any updates. And if this helps, don't forget to mark it as an answer.

Best,

Jake Zhang

Answer 2

Hi,

You have two choices :

You can configure a transfer rule or invite users with Microsoft Entra B2B collaboration.

The second option is more complicated but here is a link with the prerequisites and explanations :

https://learn.microsoft.com/en-us/power-platform/admin/invite-users-azure-active-directory-b2b-collaboration

https://learn.microsoft.com/en-us/entra/external-id/b2b-quickstart-add-guest-users-portal

https://learn.microsoft.com/en-us/entra/external-id/add-users-administrator

Sincerely,