Cfrgtkky

Instead of manually putting a newpage before begin{appendices}, how can I tell the appendix package to do this ?

If you have a chaptered document class, this would be the default behaviour. In documents with top level structure section there is no way to tell the appendix package to insert a page break. That is because sections usually do not start new pages. So you need to manually add a clearpage.

The etoolbox package provides commands for inserting commands around/within environments.
I've included some related (commented) commands you may find useful.

documentclass{article}



usepackage{appendix}

usepackage{etoolbox}



% Inserts clearpage before begin{appendices}

BeforeBeginEnvironment{appendices}{clearpage}

% Inserts clearpage after end{appendices}

%AfterEndEnvironment{appendices}{clearpage}



% Inserts clearpage before every section within appendices environment

%AtBeginEnvironment{appendices}{pretocmd{section}{clearpage}{}{}}{}



begin{document}

    section{Pre1}

    section{Pre2}



    begin{appendices}

        section{App1}

        section{App2}

    end{appendices}



    section{Post1}

    section{Post2}

end{document}