Copper-plated PCB boards protect circuits, enhance conductivity, and resist oxidation, improving the appearance of the board. The process involves preparing the copper plating solution, pre-treating the PCB board, immersing it in the solution, and performing cleaning and post-treatment. The difference between copper sinking and copper plating lies in the process and application, with copper plating being suitable for products that require high corrosion resistance, conductivity, and aesthetics.