Two factor authentication can't be turned off, but it's worthless and frankly super-frustrating when you are dealing with a lost phone. Sending a verification code to a phone at the bottom of the ocean is not exactly useful. Solutions?
iPhone XR
Getting a verification code to this iPhone was not the only method of receiving it.
Ref: Get a verification code and sign in with two-factor authentication - Apple Support
Getting a verification code to this iPhone was not the only method of receiving it.
Ref: Get a verification code and sign in with two-factor authentication - Apple Support
two factor authentication when phone is lost
