How to setup Multi-Factor authentication Sign in to Microsoft 365 with your work or school account and password as usual. When prompted for more info, click Next. You'll be asked to use the Microsoft Authenticator app. If you already have it on your phone, click Next and follow the instructions to add your account. If not, click Download now to get the app. Click the link that says “Pair your account to the app” (you’ll see it highlighted) Tap Get Codes in the app. Click ‘done’ A number will appear on your screen — type it into the app, then tap YES. Click next Enter your phone number as a backup method. Complete the "I’m not a robot" check. You’ll get a 6-digit code on your phone — enter it when prompted. Once verified, click Next, then Done. You're all set! MFA setup is complete.