\documentclass[a4paper,12pt]{article}
\pagestyle{empty}

\usepackage[utf8]{luainputenc}
\usepackage{pdfcomment}
\usepackage{hyperref}

% pdfcomment, datetime2, marginnote, bezos (soulpos.sty), soul

\begin{document}

\pdfmargincomment[subject={Test}, author={Random Guy}]{Comment}

\pdfmarkupcomment[markup=Highlight]{Highlight}{}
\pdfmarkupcomment[markup=Underline]{Underline}{}
\pdfmarkupcomment[markup=Squiggly]{Squiggly}{}
\pdfmarkupcomment[markup=StrikeOut]{StrikeOut}{}

\vspace*{2\baselineskip}
\pdffreetextcomment[type=freetext,height=1cm,width=4cm,hoffset=0cm]{Free text}

\pdffreetextcomment[type=callout,height=1cm,width=4cm,hoffset=5cm]{Free text}

\pdffreetextcomment[type=typewriter,height=1cm,width=4cm,hoffset=10cm]{Free text}

\pdfsquarecomment[width=1cm, height=1cm, hoffset=0cm]{}

\pdfcirclecomment[width=1cm, height=1cm, hoffset=2cm]{}

\pdflinecomment[type=line,line={0 750 50 800}]{}

%\pdfannot width 10ex height 10ex {
%/Subtype /Line
%/L [0 0 100 100]
%}

\section{A}

\url{http://www.tug.org/texworks/}

sec.~\ref{sec:a}

\clearpage

\subsection{aä®€}
\label{sec:a}

\section{\LaTeX}

\end{document}
