- Google Drive
A .docx file is a Microsoft Word XML Format Document file, a kind of Microsoft Word document. Starting in Microsoft Office 2007, .docx files became the default file type. You may have noticed when you open older .doc files made in Word 2003, that they opened in 'Compatibility Mode'.
Associated programs: Microsoft Word 2007, Microsoft Word 2008 (MAC), OxygenOffice Professional (Linux), Word 2010