Please provide a minimal working example (mwe) next time.
\documentclass[twocolumn,a4paper,12pt]{article}
\usepackage{lipsum}
\author{A. Author}
\title{How to a Make Two-column Format}
\begin{document}
\maketitle
\section{Chapter}
\lipsum[1]
\section{section}
\lipsum[1]
\end{document}