The policy option for Mobile app push authentication is located in the OOBA-SMS section in the "MobileID/Time-Based" policy


SMS push supports 4 types of user authentication

MethodRemarks
ConfirmConfirmation by simply replying 'Y' 
Onscreen CodeVerification by replying with the onscreen code
PINVerification by replying with the PIN of the user's MobileID token
OTPVerification by replying with a OTP generated from the user's MobileID token