Put [^1] where the marker should go and write [^1]: followed by the note on its own line. The renderer numbers the notes, links each marker to its note and collects them at the bottom. Footnotes are a GitHub Flavored Markdown extension, not core CommonMark.
All ways to write it
A marker in the text and the note anywhere in the file.GitHub Flavored MarkdownText with a note.[^1] [^1]: The note itself.
GitHub Flavored MarkdownText.[^source] [^source]: Named notes are still numbered in order.
Example
You type
Exports keep panels as callouts.[^1]
[^1]: When the panel style setting is Callout.Questions
Can a footnote have more than one paragraph?
Yes. Indent the following paragraphs by four spaces under the [^1]: line.
How do I cite sources in Markdown?
Footnotes are the simple option. Pandoc and Quarto also support citation keys like [@smith2020] with a bibliography file.
Footnotes in Confluence
Footnotes are one of the extensions Markdown Importer lists in its known issues: they may not convert as expected on import, so check those pages after importing, or turn the notes into a short "Notes" section first.