\appendix ¶Synopsis:
\appendix
This does not directly produce any output. But in a book or
report document it declares that subsequent \chapter
commands start an appendix. In an article it does the same for
\section commands. It also resets the chapter and
section counters to 0 in a book or report, and
resets the section and subsection counters in an article.
In this book
\chapter{One} ...
\chapter{Two} ...
...
\appendix
\chapter{Three} ...
\chapter{Four} ...
the first two will generate output numbered ‘Chapter 1’ and
‘Chapter 2’. After the \appendix the numbering will be
‘Appendix A’ and ‘Appendix B’. See Larger book template,
for another example.
The appendix package (https://ctan.org/pkg/appendix)
adds the command \appendixpage to put a separate
‘Appendices’ heading in the document body before the first
appendix, and the command \addappheadtotoc to do the same in
the table of contents. You can change the word ‘Appendices’
with a command like
\renewcommand{\appendixname}{Specification}, as well as a
number of other features.