Unless it's a special black, e.g. with pearls or matte. The closest black from your closest auto shop will sort of do the job if you're not looking for perfection. Otherwise, special paint shops will fix you a color to match your car's color code. Can be put in a spray can, tin, nail polish bottle, etc. Of course it will be more expensive.
If you're using a spray can, you can also shake well and spray some into the lid and use a small brush to touch up spots.
As for application, just make sure you have cleaned the area well and when you touch it up don't do a rushed job and try not to coat over or "fix" too much as the ingredients will end up hurting area surrounding more than you actually fixing it. (It will take off your clear coat).
Also make sure that you have a clean micro fibre cloth with some polish handy as soon as the paint is dry protect it. Usually touch up handy men will have some sort of cream polish, so it's not too harsh. Along with a small drill polisher, which if you have, great!
