I'm trying to draw a vertical line similar to the one use in the abstract of this document, as seen below

I didn't find any good solution so far.
I'm trying to draw a vertical line similar to the one use in the abstract of this document, as seen below

I didn't find any good solution so far.
You can use or mdframed package (or tcolorbox) to create the vertical bar. Here there is a short example. Obviously, this code is only a starting point that can be expanded: arrange colours, insert italics, line spacing, font size, etc. The font used is tgpagella:
\documentclass[a4paper,12pt]{article}
\usepackage{lipsum}
\usepackage{xcolor}
\usepackage{tgpagella}
\usepackage[T1]{fontenc}
\usepackage{mdframed}
\begin{document}
\begin{mdframed}[linewidth=1.5,linecolor=red, topline=false,rightline=false,bottomline=false]
\textbf{\textcolor{red}{Abstract}} \textit{\small \lipsum[1]}
\end{mdframed}
\end{document}
Addendum by comment of the user @Caladay: mdframed has differents options: you put
innertopmargin=-.1em, innerbottommargin=0em
and with the parameter -.1em (decrease) the lenght of the vertical red line. With 0em the bottom vertical red line is aligned. With -.1em it is a bit lower. However you can choose your best lenght.
\documentclass[a4paper,12pt]{article}
\usepackage{lipsum}
\usepackage{xcolor}
\usepackage{tgpagella}
\usepackage[T1]{fontenc}
\usepackage{mdframed}
\begin{document}
\begin{mdframed}[linewidth=1.5,linecolor=red, innertopmargin=-.1em, innerbottommargin=0em, topline=false, rightline=false,bottomline=false]
\textbf{\textcolor{red}{Abstract}} \textit{\small \lipsum[1]}
\end{mdframed}
\end{document}
\begin{document}
\lipsum[1] \begingroup \leftskip=1cm \begin{mdframed}[linewidth=1.5,linecolor=red, topline=false,rightline=false,bottomline=false] \textbf{\color{red} Abstract} :\textit{ \lipsum[1] } \end{mdframed} \endgroup
\section{Introduction}
\lipsum[1]`
Sebastiano suits with your requirement, then you have to click the tick mark, this is the best way you show your tribute ....please...
– MadyYuvi
Apr 23 '20 at 14:07
\documentclass{...}and ending with\end{document}.`` – Alessandro Cuttin Apr 22 '20 at 20:49