\documentclass{mwart}
\usepackage{amsfonts}
\usepackage{amsmath}
%\usepackage[hmargin=2cm,vmargin=2cm]{geometry}
\usepackage[utf8]inputenc}
%\usepackage[cp1250]{inputenc}
\usepackage{polski}
%q\usepackage[OT4]{fontenc}
\begin{document}
    Łukasz Solak 306462
    \section { sekcja }
    \subsection { podsekcja }
\end{document}