12/06/1993
PDF was developed as a method to share documents, including text formatting and inline images, among users in different platforms and computers who may not have access to mutually-compatible application software. It was among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format.
Before the rise of the World Wide Web and HTML documents, PDF was popular on desktop publishing workflows.
Adobe holds patents to PDF, but licenses them for royalty-free use in developing software complying with its PDF specification.