The customization of simple freight elevators mainly involves the following aspects:

1. Elevator specifications: Determine the size, load capacity, lifting height, and other specifications of the elevator based on usage needs.

2. Elevator material: Choose suitable elevator materials such as steel, aluminum alloy, etc. to ensure the stability and durability of the elevator.

3. Elevator control system: Choose a suitable elevator control system, such as PLC, frequency converter, etc., to ensure the stability and safety of elevator operation.

4. Elevator decoration: Choose appropriate elevator decorations based on the usage environment and needs, such as elevator doors, elevator lobbies, elevator interior decorations, etc.

5. Installation and commissioning: Elevator installation and commissioning is an important part of elevator customization, which needs to be carried out by the elevator installation company.

The above are the main aspects of customizing a simple freight elevator. The specific customization process requires detailed design and planning based on usage needs and environment.