Sooner or later, you’re going to get a new phone or misplace your phone—or otherwise find yourself in a situation (such as a secured location or a no-phone-allowed classroom) where you can’t use your MFA-registered device.
That’s why it’s always a good idea to generate a list of backup passcodes for future use. Fortunately, there’s a detailed KnowledgeBase (KB) article that’ll walk you through the simple steps. See Generating Backup Passcodes for Future Use.
Important note: Backup passcodes should be stored offline in a secure place, and they expire after 4 months.