Footnotes

• Org allows for the easy creating of footnotes ¹
  
• One must distinguish a reference from a footnote. The reference is a pointer, though it may point no further than itself.
  
• Footnotes must begin at column 0. One can create these manually or automatically.
  

• Numbered ²
  
• Named ³
  
• No-name inline, which like parenthetical comments provide additional information or clarification ⁴. These are placed within the text. They can be as long as necessary. Note: While inline footnotes provide additional information similarly to parenthetical comments, they are formally footnotes and will be treated as such upon export, appearing at the bottom of the page or document, not within the text like parenthetical comments.
  
• Named/inline ⁵ An inline definition of a footnote, which also specifies a name for the note. When you wish to reference the same note multiple times, use this and then follow it up with ⁵.
  
• In all these formats the colon `:` serves as a delimiter.
  

There is one main command that "handles" footnotes in org: org-footnote-action bound by default to C-c C-x f. It does different things depending on where the cursor is in the document. If the cursor is on a reference, it will jump to the footnote definition (whether inline or otherwise). If it is on the definition it will jump to the reference. If on nothing it will create a new footnote.
The variable org-footnote-define-inline determines the position of the definition.
When called with a prefix key org-footnote-action provides additional actions:

s Sort footnote definitions by reference sequence.
r Renumber simple fn:N footnotes.
S First rename, then sort.
n Rename all footnotes into numbered footnotes.
d Delete the footnote at point, including definition and references

These commands are necessary because org makes no effort to sort footnote definitions. To make this happen automatically, set this variable: org-footnote-auto-adjust⁶

Two other commands are worth mentioning:

C-c C-c Quick way to jump back and forth between reference and footnote.

C-c ' Edit footnote definition in a separate window.