From the main menu, tap Settings and privacy.
Tap Security and account access.
Tap Two-factor authentication.
There are three methods to choose from: Text message, Authentication app, or Security key.
Once enrolled, when you log in to your account, you'll be prompted to provide the two-factor authentication method you used during your previous login, along with your password. You’ll also see the option to Choose a different two-factor authentication method. If you’d like to proceed, simply tap the prompt to select a different method. Follow the onscreen instructions to finish logging in.