DOCX — Microsoft Word Document
DOCX is the default file format of Microsoft Word since Word 2007, replacing the older binary .doc format. Technically it's a ZIP archive containing XML files that describe the document's text, structure and styling — an open, documented standard (ECMA-376 / ISO 29500) that other software can implement.
A DOCX file is a working document: it's meant to be edited, tracked, commented on and revised, in contrast to PDF which is meant to be final.
What Word (DOCX) files are used for
- Drafting and collaborating on documents of every kind
- Documents with tracked changes and comments
- Templates: letters, reports, essays, proposals
- Anything that will be edited again later
Advantages
- Fully editable, with rich formatting, styles, tables and images
- Broad compatibility: Word, Google Docs, LibreOffice, Pages all open it
- Open standard — not locked to Microsoft software
- Much more robust than the legacy .doc binary format
Limitations
- Rendering can differ slightly between applications and installed fonts
- Remains editable — not ideal for documents that must not change
- Larger and more complex than plain text for simple content
- The legacy .doc format (pre-2007) is a different, incompatible format
How to open a Word (DOCX) file
Microsoft Word opens DOCX natively, but you don't need it: Google Docs (free, in the browser), LibreOffice Writer (free, desktop) and Apple Pages all open and edit DOCX files. To share a DOCX so that it looks identical everywhere, convert it to PDF first.