Steps to delete your own Office 365 user account that you use at work
Note:Before you delete a user from your Office 365 business subscription, we recommend you save the user's email and OneDrive data, and take other steps to protect your business.
Go to the Office 365 admin center.
In the Admin center, select Users.
On the Active Users page, choose the names of the users that you want to delete, and then select Delete user.