A frame is like a skeleton for a car or truck. Just like our bones hold our body up and keep us from falling apart, the frame of a vehicle supports everything that makes it move. The frame is made up of long pieces of metal that are welded together to form a tough, strong structure.
Think of the frame as the foundation for a house. It needs to be strong and sturdy so that the walls and roof don't collapse. In the same way, the frame of a vehicle needs to be strong so that the weight of the engine, wheels, and all the other parts don't crush it.
The frame also holds all the parts of the car in the right place. It keeps the wheels and tires from wobbling and prevents the engine from shifting around. Without a good frame, the car would be shaky and unstable, and it might not even be safe to drive.
So, in short: a frame is like a strong, metal skeleton that holds a car or truck together and keeps it from falling apart. It's the foundation that supports everything that makes the vehicle move.