An automatic car sounds as if it’s car that drives itself. In fact, it’s one in which the gears change automatically. The driver has to steer the car and operate the other controls such as the accelerator and brakes.
The gear changes as the cars speeds up or slows down, and when it has to climb or descend a hill. This enables the engine to drive the wheels with more power when it is needed. In a car without an automatic gearbox, the driver chooses when to change gear. This gives the driver more control over the car, but an automatic car is easier to drive.