Sometimes Microsoft needs to verify your identity to help make sure that you—and only you—have access to your account. The easiest way for you to verify your identity is with an app on your mobile device. Identity verification apps are:
Free. Apps don't require text or email to verify your identity, so you won't incur any usage charges on your phone service. (You can still choose to get a security code via text or email if you don't have the app handy.)
Instant. Open the app at any time to verify your identity.
Always there. If you're on the move, identity verification apps can generate security codes even when you can't get phone service.
Identity verification apps work differently depending on the platform your mobile device uses. You can verify your identity with an app in one of two ways:
Enter a security code. Some identity verification apps generate random security codes every thirty seconds. When you need to verify your identity, get the latest code from the app and enter that on the verification site. These codes work even when your mobile device is offline, so you don't need to worry about having service to receive an email or SMS message.
Approve a notification. With this kind of app, you no longer need to enter security codes. Instead, you'll receive a notification on your device when you need to verify your identity. Open the notification, approve it, and you're done.
First, download an identity verification app for your phone. The Microsoft Authenticator app is available for Windows Phone, Android, and iOS. If you have a different mobile operating system, there are other options available. Search for "authenticator" in your app store and choose from the list of available apps.
To add your Microsoft account to the Microsoft Authenticator app, follow these steps:
Open the Microsoft Authenticator app on your phone and select Add account.
Choose Personal account, then sign in to your Microsoft account.
Once your account is successfully added, you will see an eight-digit number underneath your account name. This number changes every thirty seconds so that you never use the same verification code twice. The next time you're asked to enter a verification code to sign in, you can open the app to find your code instead of waiting for a text message.
If your phone is lost or stolen, you should cancel any identity verification apps to help keep your account safe. If you turn off your apps and then find your phone, you can always add your account again.