Setting up Microsoft Authenticator Mobile App
Download the Microsoft Authenticator. You can get the app from either the "App Store" (iPhone) or "Goolgle Play" (Android).
For Business accounts, choose "Skip" in the top right.
Choose "Add a work or school account".
Select "Sign in" for a simple sign on experience.
Input your Business Microsoft account credentials.
Once you are signed in you can select the "passwordless" option. This will allow you to confirm any sign in attempts to your Microsoft account, by simply pressing "yes" or "no" as it appears on the screen.
NOTE: Some images are hidden due to copy protection built in to the app.