\documentclass[a4paper]{article} %
\usepackage{graphicx,amssymb,hyperref} %

\textwidth=15cm \hoffset=-1.2cm %
\textheight=25cm \voffset=-2cm %

\pagestyle{empty} %

\date{} %

\def\keywords#1{\begin{center}{\bf Keywords}\\{#1}\end{center}} %

% Please, do not change any of the above lines


\begin{document}

% Type down your paper title
\title{Sample \LaTeX\ abstract NTC2022}

% Authors
\author{Author 1 \\ %
       University of Author 1 (Country) \\ \\ % Affiliation 1
       Author 2 \\ % If any other author with different Affilation
       University of Author 2 (Country) \\ \\ % Affiliation 2 (if needed)
       % New author \\
       % New affiliation \\
       % Add authors and affiliation as needed
       \tt{CorrespondingAuthor@university.com} % Only one corresponding e-mail
       }%


\maketitle

\thispagestyle{empty}

% The abstract

\begin{abstract}
This is a sample abstract for submitting at NTC2022 \cite{ntc2022}. You should send the tex file and a pdf version of your proposal. Each abstract should not be more than \textbf {one page in length}, including figures and references. The \textbf{paper size should be A4} (210 mm $\times$ 297 mm), and the \textbf{margins should be as defined in the template}. As in this example, please use the commands provided in the template for formatting the title, the list of authors and the  references.
\end{abstract}

\keywords{Abstract submission} % Write down at least 3 Keywords

\begin{thebibliography}{100}

\bibitem{ntc2022} \url{https://ntc2020.math.unideb.hu/}

\end{thebibliography}

\end{document}