What is a DOCX file?
DOCX is the default document format of Microsoft Word since Office 2007. Despite the single extension, a DOCX file is a ZIP archive containing XML files for the text, styles, numbering and settings, plus a media folder with the embedded images. Rename a .docx to .zip and you can browse its parts.
The format is an ISO standard (ISO/IEC 29500, Office Open XML), which is why LibreOffice, Google Docs, Pages and many converters can read and write it. Formatting is expressed as styles and runs, so the same document can reflow when fonts or page sizes change, unlike a fixed-layout PDF.
When DOCX is the right choice
Strengths
- Fully editable: text, styles, tables, comments and tracked changes
- Opened by Word, LibreOffice, Google Docs and most office suites
- Compact: the ZIP container compresses the XML and reuses images
Limitations
- Layout can shift between applications and when fonts are missing
- Not suitable as a final, unalterable copy; recipients can edit it
- Macros are not allowed in DOCX; macro documents use DOCM
How to open a DOCX file
Microsoft Word, LibreOffice Writer, Google Docs, Apple Pages and WPS Office all open DOCX. Without any of them installed, convert the file to PDF and read it in a browser: Word to PDF keeps the layout intact.
How to convert a DOCX
For sharing and printing, Word to PDF is the usual route. DOCX to TXT extracts plain text, DOCX to RTF targets older editors, and DOCX to ODT moves the document to the OpenDocument world. The reverse direction, PDF to Word, rebuilds an editable file from a PDF.