\documentclass{article}

\usepackage{geometry}
\usepackage[utf8]{inputenc}

\geometry{
	paperwidth=9cm,
	paperheight=7cm,
	margin=0.1cm,
    top=-0.4cm
}

\title{My document}
\author{Vincent Kuhlmann}
\date{7 September 2021}

\begin{document}
\maketitle
\section{Introduction}

Hello everyone!
\end{document}