\documentclass[12pt,onecolumn]{article}
\usepackage{blindtext}
\usepackage{float}
\usepackage{multicol}
\usepackage{graphicx}
\title{Something}
\author{Someone}
\begin{document}
\maketitle
\begin{multicols}{2}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
\begin{figure}[H]
\includegraphics[width=\linewidth]{example-image-a}
\caption{Some image}
\end{figure}
Curabitur dictum gravida mauris.
\blindtext
\end{multicols}
\end{document}