docx In an effort to create an open document standard, Microsoft in collaboration with ISO/IEC and Ecma, developed the Office Open XML standard in 2006. One of the filename extensions supported in this specification is the .docx extension, a text document filename extension. The .docx was introduced in Microsoft Office Word 2007 and has been supported ever since in later iterations. It has become the default filename extension for all text documents produced using Microsoft Office Word. Given the open source nature of the XML specification, more alternative document processing applications support read and write capabilities on documents saved with the .docx filename extension. This is in comparison to the .doc filename extension which is a proprietary asset owned by Microsoft.
pdf The .pdf file format extension was developed by Adobe systems in 1993 as a means of presenting documents in a consistent manner across different platforms, hardware, operating systems, and applications. The format was not released as an open source document format until 2008, though minimal proprietary technologies still controlled by Adobe Systems exist in the format. Every .pdf document carries with it the necessary meta information required to properly reconstruct the text, fonts, and graphics used to produce the document. This ensures that documents will be viewed in exactly the same way the author intended regardless of the device used to open the document. From conception to date, Adobe Systems has continued to support the format adding features with every iteration of the standard including hardened algorithms for document encryption and privacy. Today, many freely available readers exist allowing you to open and view .pdf documents and create or convert other file formats such as .jpeg and .doc into .pdf documents.