How to Recover a Deleted Microsoft 365 User Account

Step 1: Log in to Office 365 with Admin privileges. start by logging into office.com using an admin account.
Only users with administrative privileges can restore deleted accounts.

Step 2: Once logged in, go to the Admin app from the Office 365 app launcher (the grid icon in the upper left corner).
This will bring you to the Office 365 Admin Center, where you can manage users, including restoring deleted ones.

Step 3: In the Admin Center, select Users from the left-hand navigation pane and then click on Deleted Users.
This will display a list of all users that have been deleted within the last 30 days.

Step 4: From the list of deleted users, select the name of the user whose account you want to restore.
This will open the user’s account details.

Step 5: Once the user’s details are open, you will see an option to Restore user. Click on this to begin the restoration process.

Step 6: After assigning a license (if required), click Save to complete the restoration process.
The user account will be restored, and the user will regain access to their data and services.

Step 7: To confirm the account has been successfully restored, go back to the Active users section and check for the restored user.
Their account should now be listed with all the associated services reactivated.

Credit : https://medhacloud.com/blog/restore-user-office-365/