There is a base fee for each delivery when you do the dropoff. This includes getting to the restaurant, picking up food and delivering it on a base distance. The base fee and the base distance associated with it vary by city and vehicle.
Increased base fees may occur in areas that are difficult to access and in these cases some part of the base fee might also be given after the pickup task has been completed. You can read more about these cases at the payment information of each city.