When starting an automatic car do you need to press down a bit on the gas pedal. My dad says have i say dont. He said it was something with choke?

No, You don't need to press down a bit on the gas pedal when starting an automatic car. When you turn the key in an automatic car, this tells a small computer called Electronic Control Unit (ECU) to turn the starter motor. ECU monitors the engine speed, and when it reads a speed of 500 RPM, the fuel injectors start spraying fuel and the ignition coil provides spark, to allow the engine to start running. Modern vehicles do not have a choke that needs to be used when starting them, the computer controlled fuel injection handles that.