Example of a good preamble setup

Dutch

Include Theorem, Lemma etc.

\documentclass[a4paper]{article}

\usepackage[utf8]{inputenc}
\usepackage[margin=2.54cm]{geometry}

\usepackage{amsmath,amssymb,amsthm}
\usepackage{commath,mathtools}
\usepackage{parskip}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{subcaption}
\usepackage[english]{babel}
\usepackage[bookmarksnumbered]{hyperref}

\title{My document}
\author{Me}
\date{September 2021}

\setcounter{secnumdepth}{2}

\begin{document}
    \maketitle

    \tableofcontents
    \section{Introduction}

    Hello everyone!
\end{document}