This plugin allows users import the entire contents of a Word 2010 (or later) file as clean HTML, retaining formatting such as headings, lists, bold and italic. The heading styles in Word such as "Heading 1" are mapped to corresponding tags in HTML such as h3, h4 (the "Heading 1" style is mapped to h3, etc.). For best results, the imported Word files should be well-styled, i.e. use standard Word named styles (e.g. "Heading 1", "List Bullet") as much as possible.
It supports .docx files only, not the older .doc format. The following Word versions support this format: Word 2007, Word 2010 and Word 2013 (on Windows); Word 2011 and Word 2016 (on MacOS). Note that files in.docm format (i.e. including macros) are not supported.
LibreOffice 5.x can also save files in .docx format, and they will import too, but generally the quality is not as good as native Word files, even if the document uses styles well.
Note also that the PHP XSL extension must be enabled on your webserver, and the plugin requires Moodle 2.7 or higher.
After installation, the Atto editing toolbar should have a new Word icon added to the files group, similar to the screenshot below.
You can click on the link to open the file selection dialog, or alternatively, just drag a file over the text area and it will be imported and converted.