Pickup is available from the airport, a hotel or another Da Nang address. The quoted price is for the car, not per passenger.
The drive is about 30 km and usually takes 40 to 50 minutes. Cars stop at the edge of the Old Town, then it is a short walk to most hotels.
The ancient town is pedestrian-only. Your driver drops you at the nearest gate and can pick you up at an agreed time.