header.tex

\documentclass{article}

\usepackage{sectsty}
\subsectionfont{\normalfont\fontsize{12}{10}\selectfont}

\usepackage{fancyhdr}
\pagestyle{myheadings}

\title{My Name \\ Assignment Title}
\author{[email protected]}

\usepackage[left=2cm, right=2cm, top=2cm, bottom=2cm]{geometry}

\usepackage{tikz}
\usepackage{graphicx}
\usepackage{multicol}
\usepackage{amsthm}
\usepackage{amsmath}
\usepackage{enumitem}

\newcommand\vartextvisiblespace[1][.5em]{%
    \makebox[#1]{%
        \kern.07em
        \vrule height.3ex
        \hrulefill
        \vrule height.3ex
        \kern.07em
    }% <-- don't forget this one!
}

\def\tvs{\vartextvisiblespace[0.7em]}

\begin{document}

\maketitle

\section*{4.1}


\end{document}