Hello, @Assane Atumane Adamo,
Welcome to the Microsoft Q&A platform!
Based on your description, I understand that you want to migrate from one Microsoft domain to another, including email and data.
Here is the process and key steps for using a third-party migration tool to migrate email and service settings from one domain to another:
- Purchase the necessary third-party migration tool licenses and create an administrator account in the target Office 365 organization two weeks before the migration.
- Initiate the domain verification process, create mailbox mapping files, schedule TTL tests, and disable directory synchronization in the source tenant three days before the migration.
- Stop incoming email flow, prepare the source and target tenants, verify the email flow and DNS changes, and begin the email migration on the day of the migration.
If you need the specific process of deploying cross-domain migrations and associated PowerShell scripts for it, please click on How to migrate mailboxes from one Microsoft 365 or Office 365 organization to another | Microsoft Learn for reference.
If you' experience issues with your deployment that you cannot resolve, please leave a comment below and I will help you move forward with your migration.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Thank you for your support and understanding.
Best Wishes,
Alex Zhang