In many cases, you'll want to generate an output file that ensures that your service bureau prints your document exactly as you want it, with no chance to accidentally make a change to your InDesign document. The service bureau's equipment will dictate in most cases what format these output files are in: EPS, PostScript, or PDF. Each option has pros and cons, and varying levels of controls, so be sure to use the option that gives you the most control and works with your service bureau 's equipment.