We'll create fresh WordPress site with Simple Footnotes Editor Button installed. You have 20 minutes to test the plugin after that site we'll be deleted.
The Simple Footnotes plugin allows you to add simple, elegant footnotes on your site.
This tiny plugin makes it incredibly simple to create those footnotes, leaving nothing to teach the site’s editors (no need to explain shortcodes or special syntaxes). It adds a button to the TinyMCE editor toolbar in the second row (i.e. the “Kitchen Sink”) that users can click to open a textarea overlay where they can enter the footnote content and then insert it into the editor with the proper syntax.