documentclass{article}
usepackage[many]{tcolorbox}
newcounter{task}
newtcolorbox{call out}%
   {enhanced jigsaw,
    breakable,
    before skip=baselineskip,
    boxsep=0pt,
    boxrule=0mm,
    colback=white, colframe={red},
    top=0mm,bottom=0mm,left=2mm,right=0mm,
    arc=0mm,
    leftrule=2mm,
    }% end of task

usepackage{lipsum}

begin{document}
lipsum[1-3]
begin{call out}
lipsum[4-6]
end{call out}
lipsum[7]
end{document}