\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[paperheight=29.7cm,paperwidth=21cm,outer=1.5in,inner=1.5in,top=1.5cm,bottom=1.5cm]{geometry}
% Custom margins
\usepackage{changepage}

% Bibliography
\usepackage{biblatex}
\addbibresource{bibliography.bib}

\title{\huge{Terms and Conditions of Service:\\ the secret weapon to abuse our privacy}}
\author{*** \\ \emph{***} \\\\ \small{\emph{Department of Information Engineering and Computer Science}} \\ \small{\emph{University of Trento}}}
\date{2020}

% Keywords command
\providecommand{\keywords}[1]
{
  \small
  \textbf{\textit{Keywords --}} #1
}

\usepackage[english]{babel}

\begin{document}

\maketitle

% ================================ %
% =========== Abstract =========== %
\begin{abstract}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed arcu urna, volutpat ac neque nec, vehicula tristique sem. Vestibulum luctus commodo libero at dignissim. Sed aliquet quam enim, in varius ipsum aliquam vel. Quisque tempus nisl nec sapien placerat suscipit in condimentum diam. Quisque gravida dui id erat tincidunt ultricies. Nulla viverra dui ante. Proin id ex tellus. Vestibulum turpis nulla, finibus non feugiat sit amet, vestibulum et dui.
Donec venenatis neque sed tellus mattis elementum. In sed est tincidunt, tincidunt eros quis, interdum orci. Nullam libero eros, malesuada nec lorem at, consectetur luctus lacus. Vestibulum et quam vel urna bibendum elementum ut in nunc. Vestibulum at pharetra ligula. Praesent condimentum semper imperdiet. Nullam eget nisi lacus. Aenean ornare libero quam, nec porttitor ligula auctor a. Vivamus eget leo ullamcorper, tincidunt dui eu, cursus ex.
\end{abstract}
% ================================ %

\vspace{0.2cm}

% ========== KEYWORDS ============ %
\keywords{Terms of Service, Privacy, Data Broker, GDPR, TOSDR}
% ================================ %

\singlespacing

\section{Introduction}
.
.
.
\printbibliography

\end{document}