Docx

DOCX is the default document file format used by Microsoft Word starting with Word 2007. It is part of the Office Open XML (OOXML) family and is defined as a zipped package that contains XML files and related resources describing the document.

Office Open XML documents use the Open Packaging Conventions (OPC). A DOCX file is a ZIP archive with a specific structure. Key parts include [Content_Types].xml, _rels/.rels, docProps/ for metadata, and word/ containing document.xml (the main content), styles.xml (styles), settings.xml, webSettings.xml, fontTable.xml, and media/ for embedded images and objects. Relationships files (.rels) map references from the package to its parts.

The document text and formatting are stored primarily as XML. In addition to body content, DOCX supports headers and footers, footnotes and endnotes, comments, revisions tracked with change tracking, and embedded objects.

Macros are not stored in standard DOCX files; macro-enabled documents use the DOCM extension. DOCX files can contain embedded media and objects, but macro storage is separate in those macro-enabled variants.

Compatibility and usage: DOCX is widely supported by word processors beyond Microsoft Word, including LibreOffice, Google Docs, Apple Pages, and WPS Office. It is designed to be backward compatible with older Word features while offering improved data integrity, repairability, and smaller file sizes due to compression.

History and standardization: Introduced with Word 2007 to replace the binary DOC format. DOCX is standardized as Office Open XML, with ECMA-376 and ISO/IEC 29500 specifications, aligned with the broader OOXML standard.