Not all applications allow you to straightforwardly save items as PDF. Most word processing, worksheet, and presentation apps let you save items to PDF from the save dialogue; but many other apps don’t often provide this option - like iTunes, iCal, Address Book, Dictionary, and internet browsers. There are times when we need to be able to save what we see on our screens so we can share the information with our co-workers, loved ones, family and friends.
PDF files are lightweight documents that you can use between computers to share information. Whether it is to be used for work or for personal matters, for emails, uploads, file sharing, or to save to USBs, it is a great format to share data between machines. The best part of it is, the format may be read in multiple platforms - either in Linux, Windows, or Mac - and the output should always look the same.