Putting ink on paper or other materials using a printing press or similar device is a basic definition of printing. In terms of desktop publishing, printing takes two primary forms: desktop printing and commercial printing.
With desktop printing, a digital file is sent to an inkjet or laser printer connected to a computer (or its network) and the printed page is available in a short while.
In commercial printing, a printing service prints a file using one of a variety of methods, often involving a printing press and printing plates. The printing method to be used affects how the digital file must be prepared. Commercial printing methods usually require very specific file preparation or prepress tasks.