If you delete an account in Office 365, it’s gone for good. But there are a few ways to get it back if you need it. ..
To delete a user, go to the Users page in the admin center. Select Active users from the drop-down menu. After that, choose Delete users to remove them from your system. Check the box next to license removal and any email aliases you wish to get rid of.
Select File from the upper left corner of the Outlook window to get to the Account Settings menu. Select Account Settings Account Settings, then pick the account you wish to remove. After that, select Remove. You’ll be warned that all offline cached material for this account will be destroyed.
Log in using your Microsoft 365 account credentials. Click Admin in the top right corner. Select Users from the drop-down menu. After that, choose Delete User from the drop-down menu to permanently remove that user’s mailbox.
When you delete an Exchange Online mailbox using Exchange Online PowerShell, the user whose account you’re deleting is removed from the Microsoft 365 admin center’s list of users. The user will be recoverable for 30 days after deletion. After the expiration of the 30-day period.
After you remove a prior user, the account will be disabled for 30 days—after which it will be permanently deleted.
