I am running # 12 wire into a 15 amp receptacle and would like to run that to a outside 20 amp receptacle can this be done

If there is any 14 gauge wire in the circuit protected by the 15 amp breaker, you cannot change the circuit breaker to a 20 amp circuit. You would have to replace any 14 gauge wire with 12 gauge wire.

If you are simply using an outside receptacle rated at 20 amps, that is permissible.

Outside receptacles must be GFCI protected circuits.