How much load DC motor can move?
This can't be answered based on the information you have provided.
It depends on what force is resisting the movement. One very strong person can pull a train, slowly. The train is very heavy, but there's nothing actually holding it back. But they couldn't pull a car with the brakes on because the brakes are on.
It also depends how strong the motor is. There should be a specified torque. We can estimate this based on the electrical power and the speed but it would only be an estimate.
It also depends on the gears. Because the gears change the speed and the torque.
It also depends on how you connect the motor to the thing being pulled. Because wheels are like gears. If you pull something with a rope for example, you put a cylinder on the motor and the rope winds up onto the cylinder. But a big cylinder will increase the speed and decrease the torque, and a small cylinder will decrease the speed and increase the torque. It's nothing to do with the motor, but it still affects how well you can pull the load.