How to download Microsoft Authenticator app?

To download the Microsoft Authenticator app, you can:

1. Go to the App Store (for iPhones) or the Google Play Store (for Android phones)
2. Search for "Microsoft Authenticator"
3. Select Install
4. Select Open to get started

You can also set up the app by: 

1. Logging into your Microsoft 365 account online
2. Clicking to set up additional security verification
3. Selecting Mobile app
4. Selecting Authenticator app
5. Scanning a QR code with your phone's camera
6. Entering a verification code sent via text to your phone
7. Clicking Verify

You can also watch this video to learn how to set up the Microsoft Authenticator app: