In order to change the enable 2FA on your Xbox Account, you will need to follow these steps:
You can set up your account on the Microsoft Authenticator app for Android or iOS.
- Go to the Security info page using the steps above.
- Select "Add sign-in method".
- Select "Choose a method" and then "Authenticator app".
Follow the on-screen instructions, including using your mobile device to scan the QR code, and then click Next. You'll be asked to approve a notification through the Microsoft Authenticator app, to verify your information. - Select Save.