Two-factor verification on your AppleID helps to keep everything nice and secure. Once enabled, you will need any two  of the following to access your iCloud account: The password to your Apple ID, a device trusted in the portal (we’ll trust devices during this process) or a recovery key (which we’ll create during this process). In other words, don’t loose your recovery key! Learn To Enable Two-Factor Verification to Secure your AppleID On The Bushel Blog