Clearance delivery issues IFR clearances to aircraft, provides restrictions to VFR aircraft as needed, and does the bulk of strip-marking.
Not all airports have a clearance delivery controller, but the service will be provided by the next highest controller.
Ground Control is responsible for providing separation to aircraft on the ground, sequencing them for departure, and coordinating with local.
Not all airports have a ground controller, but the service will be provided by the next highest controller.