Adding section header to appendix

Question

I am currently using the appendix package and would like to add some form of header to the appendix section.

For example currently my appendix starts with Appendix A as its title, I would like it to look like

APPENDIX
Appendix A
Title of Appendix A
Appendix A Content

new page

Appendix B
Title of Appendix B
Appendix B Content
and so on...

Without a page break between the Appendix and Appendix A headers just a newline.

My current latex setup is below, inputs are just individual chapters.

\usepackage{appendix}
....
\begin{appendices}
\input{appendix-outline}
\end{appendices}

Inside the appendix-outline I have

\input{appendices/test1}
\input{appendices/test2}
\input{appendices/test3}

which are just files with a this heading

\chapter{test1}
text goes here

Answer 1

Fundamentally this is similar to Start new chapter on same page as you want to avoid a page break between chapters, with the addition of APPENDIX before the first chapter. One could use

\begin{appendices}
\cleardoublepage% ...or \clearpage if you're not using the twoside option
\let\clearpage\relax
\noindent{\huge\bfseries APPENDIX\par}
\input{appendix-outline}
\end{appendices}

Here is a minimal example showing the expected output:

\documentclass{book}

\usepackage{appendix,lipsum}

\begin{document}

\tableofcontents

\chapter{A chapter}
\lipsum[1-7]

\begin{appendices}
\cleardoublepage
\let\clearpage\relax
\noindent{\huge\bfseries APPENDIX\par}
\chapter{First appendix}
\lipsum[1]

\chapter{Second appendix}
\lipsum[2]
\end{appendices}

\end{document}

The hope is that you don't run into problems around the page boundary inside the appendices. However, in such cases you might want to update \chapter to check the available space on the page (via something similar to what needspace provides).