Performing a migration from the Exchange Management Console (EMC) is relatively simple, as long as the Exchange Hybrid configuration has been validated and is functional:
To get started, connect to the Exchange Hybrid server you set up for Office 365. Open the EMC on this server. You should see both your on-premise organization and the Office 365 organization you created for the Hybrid configuration:
Ensure both organizations can be expanded.
Now navigate to the on-premise Organization and navigate to Recipient Configuration | Mailbox. Find a mailbox you would like to migrate. Right-click on this mailbox and click on New Remote Move Request…:
If the user has an Exchange archive and you plan to move this archive with the Exchange mailbox, be sure to select the Move both the mailbox and the archive option. Otherwise, ensure that Move only the User mailbox is selected and click on Next: