Add new Microsoft 365 users or synchronize users from the local Active Directory to Microsoft 365.
- If the source domain will be moved to the destination environment:
It is recommended that you use the default email address (**user@contoso.onmicrosoft.com**) in migration projects. Or you can use email addresses ending with an owned domain. After the domain name of your source tenant is changed to your destination tenant for go-live, if the final incremental migration is needed, use **Change** **mapping domain** in Fly to update the email addresses in projects in bulk.
- If the source domain will not be moved to the destination environment, you can just use different email addresses when configuring mappings in migration projects.
- Refer to the .
