Portable Document Format (PDF) is a type of document created by Adobe back in 1990s. The purpose of this file format was to introduce a standard for representation of documents and other reference material in a format that is independent of application software, hardware as well as Operating System. PDF files can be opened in Adobe Acrobat Reader/Writer as well in most modern browsers like Chrome, Safari, Firefox via extensions/plug-ins.
TEXLaTeX Source Document
TeX is a language that comprises of programming as well as mark-up features, used to typeset documents. Donald Knuth from Stanford University, is the creator of this resourceful typesetting system. Across the world, TeX is the ultimate choice of authors and publishers to produce high quality technical documents. TeX performs an outstanding job of formatting complex mathematical expressions. In conjunction with a high-quality phototypesetter, TeX competes the results generated by the best traditional typesetting systems.