\documentclass{article}
\begin{document}
Hello, \LaTeX!
\end{document}

\section{Introduction}
\subsection{Background}
\subsubsection{Details}

\textbf{Bold}
\textit{Italic}
\underline{Underline}
\emph{Emphasis}
\texttt{Monospace}

\begin{itemize}
  \item First item
  \item Second item
\end{itemize}

\begin{enumerate}
  \item First
  \item Second
\end{enumerate}

\( a^2 + b^2 = c^2 \)
\[
  \int_0^1 x^2 dx
\]
\begin{equation}
  E = mc^2
\end{equation}

\begin{tabular}{|c|c|}
  \hline
  A & B \\
  \hline
  1 & 2 \\
  \hline
\end{tabular}

\usepackage{graphicx}
\begin{figure}
  \includegraphics[width=0.5\textwidth]{image.png}
  \caption{Sample Image}
\end{figure}

\label{sec:intro}
See section~\ref{sec:intro}.

\cite{author2020paper}
\bibliographystyle{plain}
\bibliography{refs}

\begin{quote}
  Quoted text.
\end{quote}

\begin{verbatim}
  Code or text verbatim.
\end{verbatim}

\newpage                % Page break
\tableofcontents        % Table