After you've saved and accessed all the former employee's user data, you can delete the former employee's account.
Don't delete the account if you've set up email forwarding or converted it to a shared mailbox. Both need the account to anchor the forwarding or shared mailbox.
- Go to the Office 365 admin center.
In the Admin center, select User management.
Select the employee that you want to delete, and then under the user's name, choose the symbol for Delete user. Choose the options you want for this user, and then choose Delete user.
When you delete a user, the account becomes inactive for approximately 30 days. You have until then to restore the account before it is permanently deleted.
If your organization synchronizes user accounts to Office 365 from a local Active Directory environment, you must delete and restore those user accounts in your local Active Directory service. You can't delete or restore them in Office 365.