Files with the DOCM extension are documents created with Microsoft Word 2007, the word processor included in Microsoft Office. DOCM files are similar to DOCX files (Default MS Word format) and can contain various elements such as images, drawn objects, tables, links to websites and to other local files and also feature a wide variety of text formatting options and styles.

They are based on the Open XML format which stores all content in a zipped archive. The archive contains XML and RELS files stored in three separate folders named “docProps”, “word” and "_rels". Files with the RELS extension dictate how the parts of the document connect to form a single file. This archived approach makes file content more accessible. For example images and text are stored individually within the archive.

What separates DOCM files from DOCX files is the possibility of embedding macros into the document's structure. This is done via the Macro Recorder included in MS Office which can be used to save command sequences and create macros that can replicate them automatically.

How to open DOCM files

The contents of a DOCM file can be extracted individually by opening it with a data compression application (i.e. WinZip or WinRAR). The XML files of a DOCM document can be opened with any basic text editor and any web browser.

If an application doesn't feature DOCM support but can open DOCX files, changing the extension will allow users to open their files as DOCX documents without the embedded macros.