Sooner or later, your vehicle will get scratched, nicked, or dinged enough to require a touch-up. A body shop can do the work, but it will cost you. The alternative is to do it yourself. The first thing to do is get the paint and make sure it matches. To do that, look for a paint identification code printed on a sticker. You may have to search around for a bit but start with the driver's side door.
Once you have the paint, move the vehicle to a spot that's out of the sunlight and away from dust, and make sure the temperature is mild enough, about 70 degrees. Clean the area with detergent and degreaser if needed and use 220-grit sandpaper to remove any rust and smooth the surface. Apply a primer, base, and clear coat and let dry in between; use a rubbing compound to blend the touch-up spot with the rest of the paint.