Sign in with your Apple ID and password Go to settings Select security type Click on add button Enter mobile number and select two-step verification Verify the code sent to your mobile phone Now click on the trusted mobile phone number and select add button to add another mobile phone number. Select turn on button and enter the password at the end of the procedure. For more info reach http://www.referenceitpro.com/blog/apple-step-verification-lost-phone or 1-888-560-1555