Cosmetic damage sits outside most of what a service contract is written to handle, so the choice of who fixes a scratch is usually yours. The task is to sort the damage honestly, then decide which jobs you can safely do at home and which need a body shop.
Sort the damage by depth
Start with the scratch itself. Run a fingernail across it. If the nail skips over the mark, the damage probably sits in the clear coat, the protective top layer. If the nail catches, the scratch has cut through to the colour layer or the primer, and it will need more than polish. Light scuffs and swirl marks on the clear coat are usually suitable for a home polish. Deep scratches, chips that show bare metal, and cracked or peeling paint are better handled by a shop that can match the colour and seal the surface properly.
Plastic trim, bumpers and mirror covers need their own sort. Faded plastic can often be restored with a trim product. Cracked plastic usually needs replacing, and a shop or parts supplier can tell you whether the part is a simple swap.
Jobs you can do yourself
Stone chips are worth touching up soon, since bare metal invites rust. A small touch-up pen matched to your paint code, applied in thin layers, is a reasonable home job. A light polish on clear coat scuffs is another. Go slowly, test on an inconspicuous spot first, and stop if the product starts to lift the paint around the mark.
Jobs to leave to a shop
Creased dents, deep scratches through to metal, large areas of peeling paint, and any damage near lights, sensors or panel edges belong with a shop. Damage near a sensor or camera can affect systems you rely on, so ask the shop to check what sits behind the panel before you decide the job is cosmetic only. If you are unsure whether the damage reaches a structural or electrical part, hire it out.
What the contract changes
Read the contract for any mention of cosmetic items, body panels or trim. Many contracts are written around mechanical and electrical breakdown, so a scratch is usually yours to handle. If a contract does cover a cosmetic item, it should say so in the parts list, not in a general sentence. Ask in writing if you are not sure.
Before you touch anything, take clear photos of the damage in good light, with something of known size beside it for scale. Keep the photos with the contract and any receipts. If a repair you did yourself later affects a related part, those photos and receipts make the question easier to answer, though they do not settle it on their own.