What is the role of the torque converter in an Audi A4?

I'm looking to understand the inner workings of an Audi A4 and the role that the torque converter plays in its performance. Can someone explain this to me in technical detail?

A torque converter is a fluid coupling device that transfers power from the engine to the transmission, allowing the car to shift gears smoothly without stalling. In simple terms, it helps the car accelerate and maintain power at low speeds.