Fast account switching now in Office on the web
Office apps in a browser have caught up with an important feature in Office 365 for Windows – quick account switching is now available.
Almost three years ago, Microsoft added quick account switching to Office 365 for Windows.

You can save logins to several Microsoft 365 accounts; work, school, home etc and switch between them in a few moments. Heaps better than sign-out the sign-in with password each time.
Now, finally the same feature is in Word, Excel and PowerPoint in a browser. Visio on the web for Business customers.
Fast Account Switching
Go to Office.com and look at the top right menu button. It’ll have your initials or a thumbnail image. Click on that to see some account details and now, other logins available.

Sign out and Forget – look for the three dots next to each login. That lets you remove the account from the list.
Sign in with a different account – choose that to add an account to the list.
Office.com web page changes coming soon