What is a Microsoft Online Services ID?
The Microsoft Online Services ID and password are generated for you by your account administrator by using the Microsoft Online Office Subscription administration website. To access this website, your company must have a subscription to Microsoft Office 365. If you don’t have a Microsoft Online Services ID and password, contact your administrator.
When you install Microsoft Office Professional Plus, you must enter a Microsoft Online Services ID and password to activate the license and to maintain full functionality of the product. If you fail to activate and maintain the license, the Office programs go into Reduced Functionality mode after 30 days of the license not being verified.