Digital printmaking is the process of using a computer to create an image that can be printed in a limited run or edition, not a mere reproduction of the original such as a postcard. The artist can still use traditional methods to create elements of the final artwork (Check out Mark Graver) which are then edited together on a computer using a program such as Photoshop to create the final piece.
Artists use digital printmaking techniques for various reasons, but one major reason that artists choose this method is that it allows them to break free from the constraints associated with traditional printing methods like lithography and etching. One of the other key benefits of digital printmaking is not having to own or use much equipment to get the desired results which helps save time and money.
Further reading on Digital Printmaking