How to create a Office 365 mailbox in a hybrid exchange configuration?

You can use these instructions to create a mailbox from Exchange On-Premise in Office 365 Online.
You can create a user mailbox here.
1. Requirements
- You have a Hybrid Exchange. Or have just installed it.
- You have completed the Hybrid Exchange wizard.
- You have been Azure AD Exchange enabled through part 3 of This Procedure
2. Create a remote mailbox via PowerShell
Create an AD user as a test.
Or use an existing user account.

Open Exchange Management Shell and run this command:
Enable-remotemailbox remotetest -PrimarySmtpAddress remotetest@365tips.be -RemoteRoutingAddress remotetest@365tips.onmicrosoft.com


3. start a Azure AD Sync
This can be done at: https://365tips.be/how-how-to-start-a-azure-ad-sync/
Your Remotemail box has been created!

4. give the user the necessary license
This can be done manually but also automatically with a dynamic or static group. https://365tips.be/2020/01/16/how-to-add-office-365-licenses-to-personas
4. give the user the necessary license
This can be done manually but also automatically with a dynamic or static group. https://365tips.be/2020/01/16/how-to-add-office-365-licenses-to-personas
5. Want to convert the mailbox to a shared mailbox?
At https://outlook.office.com/ecp / you can click on the mailbox and convert it to a shared mailbox.

That's it ! you have now created a remote mailbox in Office 365!
Why a remote mailbox?
This leaves a recipient "behind" with a base in the Exchange On-premise. Useful for modifying multiple objects simultaneously with a script.
For mailbox management you have Active-Directory for mailflow you need a hybrid mailbox. It makes sense that you then also have a hybrid-exchange .
Read more reasons why a hybrid Exchange environment here.