Installing Microsoft Authenticator application for a service Perform these steps to install Microsoft Authenticator application for a service: Download and install the Microsoft Authenticator application from the App Store (iOS) or Google Play Store (Android). Open the Microsoft Authenticator application. Click Add to add a new account. Select the required account type. For example, work or school account, personal account, or other accounts. Scan the QR Code or specify the secret key. Note: The QR code or the secret key is generated when setting up the two-factor authentication (2FA) for your service. See, Generating the secret key for Microsoft or Generating the secret key for Google.