If I use the document download option, is the file a .doc or a .docx file?
The document is a .doc file. The plugin takes the HTML output, enables a download of it as a .doc file that Word can read, which you can then save as a docx file when you open it in Word.
Can I tweak the formatting of what appears in the document?
The plugin code injects some basic formatting styles into the document file. It sets the font as Arial, the section title font size at 24px, the field label font size at 18px, and the field value font size at 14px. You can change these by editing the plugin code. (If you want more control over the formatting, you may want to use our GM Templated DOCX plugin or our GM HTML to DOCX plugin instead.)