Where does Apple set up call forwarding?

Apple turns it on or off in Settings-Phone.

CallForwarding, also known as call forwarding and incoming call forwarding, is a function that can be set to transfer incoming calls to other mobile phones when the telephone user does not want to answer or is inconvenient to answer the phone.

Call forwarding is to provide convenience for users, so that users can decide whether to answer the phone or how to answer the phone at any time according to their own wishes.

The basic calling service of mobile communication network is the process that the calling user inputs the phone number of the called user, and then the two parties enter the call. However, for various reasons, if the called user does not receive the call and transfers the call to another phone or number at the same time, this is CF(CallForwarding), also known as call forwarding and incoming call forwarding.