\AtEndDocument ¶Synopsis:
\AtEndDocument{code}
Save code and execute it near the end of the document.
Specifically, it is executed when \end{document} is executed,
before the final page is finished and before any leftover floating
environments are processed. If you want some of the code to be executed
after these two processes then include a \clearpage at the
appropriate point in code.
You can issue this command more than once; the successive code lines will be executed in the order that you gave them.