Mention below is the step by step manual guide for Exchange migration to Office 365.
Go to EAC and open it>>Now, navigate to Office 365>>Choose on the Recipients
Choose the Migration option >> Click on Add option >> then, Select Migrate to Exchange Email Online
Now, from Select a Migration Type wizard, Select Remote Move Migration>>Click on Next
Under the Select, the users’ window, click on Add + option
Select On-Premises User>>Click on Add>> Click on Ok and Next
At this point, under Enter the Windows user account credential, add credentials of on-premises administrator account>> Click on Next.
Check if the FDQN of desired Exchange server is present or not in the “Confirm the migration endpoint” window.
Under the New migration batch name text field, enter the migration batch name in the move Configuration window.
Click the Target delivery domain for the mailboxes for migrating to Office 365
At this point, check Move primary mailbox along with archive mailbox option is selected or not.
On the Start the Batch option >>Choose one Recipient>> Ensure that start the batch option is Automatically selected
Choose checkbox of Automatically complete the migration batch >>Click New
Definitely, the manual method is one of the outstanding procedure intended for Exchange to Office 365 migration or vice-versa.