Depends on the actual damage. Small scratches can often be buffed out. Deeper but still narrow scratches/scrapes can be filled using color matched (Spectrum Color brand) paste.
Larger gouges usually need to be ground out and then patched. Finally if the glass fibers are exposed, a more complex process may be needed.
That said, if you don't care about the color match, MarineTex is a simple way to fix small to medium damage. With all fixes, there will be sanding, compounding and polishing if you want the repairs to be smooth
As DennisG mentioned, more info in the form of a few pictures will get you better responses.