Chris Roberts

Annie provides comprehensive annotation options, including footnotes and highlighting. If Tippy is installed, footnotes can be displayed inline using tooltips. Also, footnotes are placed at the end of the post. For highlighting, you are able to use default highlighting styles or define your own.

Annie

Provides comprehensive annotation tools for WordPress posts.

maurobringolf

This plugin gives you a shortcode to make numbered references to footnotes, directly from your post content. Footnotes are listed and enumerated automatically at the end of your post 
content, reusing all existing styles of your site. All references become anchor links guiding the user to the footnote section of the post.
We would love to hear and discuss your feedback in a <a href="https://wordpress.org/support/plugin/mnml-footnotes/reviews/" rel="ugc">review</a>. If you want to report a bug or have a feature request, please do so via the <a href="https://github.com/maurobringolf/mnml-footnotes" rel="nofollow ugc">GitHub repository</a>.
<h3>Usage</h3>
To make a new footnote reference in your content you can use the shortcode mnml_footnote in the following way:
This is your regular post content and the shortcode by this plugin looks like this [mnml_footnote] Easy, right? [/mnml_footnote]
Everything inside the shortcode will be moved into a footnote and replaced by a numbered reference link to it. In this example the footnote content would be “Easy, right?”.

Annie vs MNML Footnotes