.docx is a file extension for documents created using Microsoft Word Processor called “WORD or MS Word”. Microsoft word is word processor with desktop publishing capabilities. The .doc files can contain formatted text, images, tables, graphs, charts, page formatting, and print settings. It is the default file extension used by Microsoft Word Versions 2007 onwards. Prior to Microsoft Word the default extension was .doc. Important: .docx files cannot be opened with MS Word versions prior to 2007. The only way to open the newer file extensions with older versions of MS Word is to use a Microsoft Compatibility Pack. This however has limitations. Not all older versions can use the compatibility pack