WHAT IS USED TO INPUT A HAND DRAWN IMAGE TO THE COMPUTER?

The image can be scanned and saved in the computer as a graphic file. Obviously, you would need a device called a scanner (commonly, a flat-bed scanner taking A4 paper) which is linked by a USB cable to your computer. There are also printers that will also scan.

There are also devices that can be drawn on using a special pen, that while drawing an image on the device, the result appears on your computer's monitor. You then save the completed image as a graphic file.