Centripetal force exists in inertial frame. Centrifugal force comes into play on a non inertial frame. (here for eg. take the non inertial frame on the revolving body itself)
CENTRIPETEL FORCE IS REAL EXISTING FORCE...... whereas CENTRIFUGAL IS A PSEUDO FORCE.... which is a reactive force for the centripetel force..... so it is actually called as CENTRIFUGAL REACTION and not as CENTRIFUGAL FORCE....
Centripetal force exists in inertial frame. Centrifugal force comes into play on a non inertial frame. (here for eg. take the non inertial frame on the revolving body itself)