Step 1: Launch SPMT. Using the same Microsoft 365 username and password you used when you originally submitted the job, select Sign In.
Step 2: After you sign in, a screen displays any paused migrations, providing details about what has been completed and what remains.
Step 3: If you want to add additional migration tasks, select Select new sources and destinations; otherwise, select Next. Your migration jobs will be resumed. If you are migrating files from an on-premises SharePoint Server, you are prompted for your username and password for that site.