The bodywork of a car is the metal shell you see from the outside — the doors, the roof, the bonnet, the wings. It is not the engine, not the wheels, not the windows, and not the seats inside. If you scrape a wall, you hurt the bodywork. In a garage, people also say “bodywork” for the job of fixing that shell: beating out a dent, putting on new paint. That is a small stretch from “the shell itself” to “work on the shell,” but both uses are normal and nobody minds. British speakers use this word every day; American speakers more often say “the body” or “body panels.” It is a practical word — not slang, not fancy — the word mechanics and insurance people use. You can use it for buses and vans too. An older, smarter-sounding word for the same idea, especially on a fine car, is coachwork.