If you forgot your username of Microsoft office setup account then you have to follow the given method to recover it.
Get Microsoft Office 365 Setup here : office.com/setup
What to do If I Forgot Office for Business Username?
You can recover your username by given methods.
1. If Office 2016 is installed, open any Office app to see your username:
You can know your username by using office apps.
Open any Office application, for example Word or Excel.
- Select File. If you didn’t open an existing document, you may need to create a new document to see the File menu.
- From the navigation on the left, select Account.
- Under Product Information is the name of your Office product and the phrase, Belongs to: along with the account associated with this version of Office.
2. Contact your admin for your username and password:
you have to contact your admin who can retrieve the username and reset the password for your Microsoft office for work or school account.
For more details, visit : www.office.com/setup