\documentclass{report}

\setcounter{secnumdepth}{6}
\setcounter{tocdepth}{6}

\begin{document}

\tableofcontents

\chapter{chapter}

\section{section}

\subsection{subsection}

\subsubsection{subsubsection}

\paragraph{paragraph}

\subparagraph{subparagraph}

\end{document}
