PDF (Portable Document Format) - A PDF is a file format that captures all the elements of the original document as an image that you can view, navigate or print from.
It can be viewed across multiple platforms and devices without the need to have the original software that created it.
The ability to embed fonts within the file means it is the gold standard for commercial printing as a properly created file will never vary.
EPS (Encapsulated Postscript) - This is a vector based format that is essentially self contained and can be placed inside other programs. Commonly used for wide format or signage work.
JPEG or JPG (Joint Photographic Experts Group) - A common file format for saving images from cameras and those for use on web pages. It uses a compression formula to save images resulting in a considerably smaller file size but does this at the cost of a reduction in quality. JPEGs can be used in print work but are generally best in their original saved file and not repeatedly edited or resaved.