\documentclass[12pt]{article}
\usepackage{amsmath} %koniecznie
\usepackage{amssymb,amsfonts,amsthm}%dodatkowo
\usepackage[polish]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{setspace}

\title{Title}
\date{}

\begin{document}
\maketitle

%tresc

\end{document}