Clearance delivery delivers your clearance. You contact them first at nontowered fields prior to operating IFR after you file on the phone. If there is no tower or CD you call a FSS to get your clearance.
example "Portland clearance, Cessna 5440Hotel, on the ground Stark's Twin Oaks, ready to copy IFR Salem"
Then you copy the CRAFT they give you and your read it back. "Cleared to Salem as filed. Maintain 4000, expect 5000 after 5 min., contact Portland Departure 126.0, squawk 4321, hold for release"