When you set up any multi-factor authentication (MFA) option, you have the option of creating a recovery code. Keep this code in a safe place.
If you are unable to use your existing MFA option(s), you can use the link at the bottom of this screen to complete sign-in:
NOTE: A recovery code can be used only once. Each time a recovery code is used, a new code can be issued, and the original code becomes invalid.