Corrado Franco

This plugin allows one to create footnotes by using markdown notation. 
It is for footnotes only. No other markdown tag is taken into account
Example:
<pre><code>I have more [^1] to say up here.

[^1]: To say down here.
</code></pre>
If used with jetpack and enabled markdown, it only shows the buttons without modifying the text content. 
Unlike jetpack-markdown, footnotes will appear in the exact point where they have been inserted. To go back to text mode click on the footnote number.
N.B 
This plugin also works with Gutenberg. But the button only appears in the Classic Editor. 
For now with Gutenberg enter the codes directly.
<h3>Configuration</h3>
No configuration is necessary.
Considering that this plugin, like others working with “markdown”, parsing the page every time I load it, I highly recommend using a caching plugin.
Customizing Footnote Layout
If you want the footnote number to be logically separated from the note (for CSS targeting) but want to prevent unwanted line breaks or extra spacing caused by WordPress’s automatic paragraphs, you can add the following CSS to your theme:
<pre><code>/* Ensure the footnote stays inline or as a specific block */
p > span.footnote {
 display: inline-block;
}

/* Remove extra spacing from the paragraph containing the footnote */
p:has(> span.footnote) {
 margin-bottom: 0;
 margin-top: 0;
 padding: 0;
}
</code></pre>

Blank Footnotes

Simple plugin to show footnotes using markdown notation.

Florian TIAR

vhbelvadi

Based on the now unsupported fd-footnotes plugin, Footnotation provides 
an easy way to add footnotes to your posts.
The syntax is retained from fd-footnotes which means it is natural, simple to 
understand, and degrades gracefully even if the plugin is removed. Bidirectional 
links are created automatically between a footnote and its position in the main 
content where the footnote was referenced from so that readers can refer to 
a footnote and return to their place in the text they were reading, with ease.
To make a footnote, type it inline within arbitrarily numbered square brackets:
<pre><code> [7. Example footnote.]
</code></pre>
The syntax is important. Each pair of square brackets must contain a number 
followed by a full stop and a space and then have the footnote text itself.
Neither do the numbers have to be in order nor do they have to be unique. All 
footnotes will be re-numbered automatically.
<h4>Settings</h4>
Show footnotes only on single posts or pages: This option hides the list of 
footnotes on the main blog page but retains their numbers which will link to the 
individual post/page URL directly.
Collapse footnotes until they are clicked on: This option hides footnotes 
initially, expanding them only when a footnote reference is clicked on.
Match footnote marker colour to surrounding text: This option makes sure the 
footnote reference marker matches the body text (academic style). The default 
option is to have the footnote marker match the website’s default link colour 
(web style).
NB Anything from links to formatting to images may be included inside a 
footnote, except square brackets.
NB Multiple footnotes with the same text and number will leave you with incorrect 
footnotes. Make sure either that all footnotes have different content or, two or 
more footnotes with the same content all have different numbers.

Footnotation

An easy way to add footnotes to your posts.

Blank Footnotes vs Footnotation