Can I combine red & black wire from ceiling to black wire on remote reciever
No. You currently have 2 separate switches...1 for fan on/off and 1 for light on/off, correct? You need to cap either one, red or black, and remove the switch associated with that wire and cap the wires at the old switch location. Best bet is cap the red off, and remove that switch. You could replace the switch in your 2-gang box with an electrical outlet, or just get a new face plate that only has one switch opening.