org-footnote-auto-adjust

org-footnote-auto-adjust is a variable defined in `org-footnote.el'.
Its value is

nil

Documentation:
Non-nil means automatically adjust footnotes after insert/delete.
When this is t, after each insertion or deletion of a footnote,
simple fn:N footnotes will be renumbered, and all footnotes will be sorted.
If you want to have just sorting or just renumbering, set this variable
to `sort' or `renumber'.

The main values of this variable can be set with in-buffer options:

#+STARTUP: fnadjust
#+STARTUP: nofnadjust

You can customize this variable.