LaTex template

\documentclass[a4paper, 11pt]{article}

\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{authblk}
\usepackage{lipsum}
\usepackage{geometry}
\geometry{
a4paper,
total={170mm,257mm},
left=25mm,
right=25mm,
top=20mm,
bottom=20mm,
}

\newenvironment{proof}{\paragraph{Proof:}}{\hfill$\square$}
\newtheorem{theorem}{Theorem}[section] \numberwithin{theorem}{section}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{example}[theorem]{Example}

\begin{document}
\pagestyle{empty}

\title{Your Title}
\date{}%leave it blank
\author[*]{Author A}
\author[*]{Author B}
\author[**]{Author C}
\affil[*]{\small Department1, University1}
\affil[**]{\small Department2, University2}

\maketitle
\thispagestyle{empty}

Your abstract, \cite{book}.

\begin{thebibliography}{99}

\bibitem{book}
R. Lidl, and H. Niederreiter, {\em Introduction to finite fields and their applications.} Cambridge university press, 1994.

\end{thebibliography}

\end{document}