Managing security settings and protections in Outlook on the web for business
Go to https://account.live.com/proofs and click on Add another way to sign in to your account.
On the next screen choose "Use an App".
On the "Set up the Microsoft Authenticator app" page, click set up a different Authenticator app.
This should get you to a page that displays a QR code. Choose I can't scan the bar code
This should get you to