\documentclass{article}

\usepackage{mkessler-mathfig}

\begin{document}
    test
\[
    \begin{tikzcd}
        A \ar{r} &  B
    \end{tikzcd}
\]
test2:
    \begin{tikzpicture}
        \draw (0,0) rectangle (10,10);
    \end{tikzpicture}
\end{document}