But it is right there only hidden from your eyes.
There is 4 types of call forwarding:-
2. Call forward if busy – Forward incoming call to another number if you’re on call.
3. Call forward if not answered – Forward the incoming call to another number if it is not answered for a predefined period of time.
4. Call forward if not reachable – Forward incoming call to another number if the phone is switch off or without signal.
iPhone allows you to setup absolute call forwarding to direct all calls to another phone number.