These files describe the copper found on each layer of your Printed Circuit Board in a format that a CAM (computer-aided Manufacturing System) can understand. The manufacturers would then utilize this image to develop the PCB with ease. Nowadays, Gerber files offer directives to laser plotting equipment. Gerber files, though efficient, do not handle Drill Hole information. So for the manufacturer to know where they are supposed to place every drill hole in your PCB, you have to send them a separate file known as a Drill File.