Most mobiles take the same codes, but not every carrier, and “turn it off” differs too. Each page below gives the code to forward only the calls you miss (your phone rings for 20 seconds first), the optional busy and switched-off codes, the forward-everything code, and the one that cancels them, with whether that carrier supports it and where we checked.
A forwarding code only moves the call. Delusia gives your business a number to forward to and an AI receptionist that answers in your name, books the appointment or takes the message, and texts the caller back. If you use Delusia, Phone Setup shows these same codes with your own number already in them, and can text them to your phone as a link.