In doing so, I had to type my email and password, and then enter my two - factor authentication code before I could start using the app. (windowscentral.com)
Backup codes are generally used for occasions when you lose your phone, or can not receive authentication codes by any other means. (androidauthority.com)
Ideally, that means using an app that generates authentication codes on your phone or a physical hardware token. (howtogeek.com)