To put it bluntly, if the appearance of the car body is damaged and deformed, the sheet metal process is needed to restore the original appearance.
Basically, the tool used is a hammer. With hammers of different shapes, the iron block is placed behind the sheet metal part and hammered repeatedly to shape it.
If necessary, use the Appearance Restorer. This thing actually belongs to welding. Weld the iron ring on the car body and pull it out with the hook. Used to repair the sunken part.
The large flat body is usually difficult to put back in place, so it is sometimes used to turn off the fire. That is, local heating and cooling make the iron sheet shrink.
The ultimate goal is to restore the damaged body to its original appearance.