PDF is short for Portable Document File.
Adobe created the open standard document exchange format in 1993 and the company says it "is the global standard for capturing and reviewing rich information from almost any application on any computer system and sharing it with virtually anyone, anywhere."
Formally known as ISO 32000, there are over 1 billion PDF files available globally.
PDFs are practically universal, with all platforms having a way to view and print the documents. This includes desktop OS like Windows, mobile OS like iOS, Android and ereaders.
The files can be encrypted, made editable and sent easily via email.
Keeping the original file intact, a PDF will preserve source file info including text, drawings, multimedia, video, 3D, maps, full-color graphics, photos, and even business logic.
PDF documents are also searchable like a word document.
Related software tools
Adobe Reader (Freeware)
Adobe Reader is free software for opening, viewing and printing of PDF files.
Adobe Reader for Mac OS X (Intel) (Freeware)
Adobe® Reader® is free software that allows everyone from business professionals to home users to easily and reliably view, print, and search PDF files using a variety of platforms an