Question: How would I create the following structure in LaTeX?

[![enter image description here](https://i.stack.imgur.com/mVV83.png)](https://i.stack.imgur.com/mVV83.png)

Answer: 
You can use `tcolorbox` to get this formatting. Here is an MWE.

```
\documentclass{article}
\usepackage{tcolorbox}
\tcbuselibrary{skins,hooks}

% Only if you want to change font
\usepackage{fontspec}
\setmainfont{Roboto}

\newcommand\fancybox[3]{%
\tcbset{
    mybox/.style={
        enhanced,
        boxsep=0mm,
        opacityfill=0,
        overlay={
            \coordinate (X) at ([xshift=-1mm, yshift=-1.5mm]frame.north west);
            \node[align=right, text=#1, text width=2.5cm, anchor=north east] at (X) {#2};
            \draw[line width=0.5mm, color=#1] (frame.north west) -- (frame.south west); 
            }
        }
    }
\begin{tcolorbox}[mybox]
    #3
\end{tcolorbox}
}

\definecolor{MyPink}{HTML}{7F007F}
\definecolor{MyGrey}{HTML}{838383}
\definecolor{MyGreen}{HTML}{02856B}

\begin{document}

\fancybox{MyPink}{Define Situation}{
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley 
}
\noindent
\color{MyGrey}{\em It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.}

\fancybox{MyGreen}{A Numbered List}{
    Some writing before list:
    \begin{enumerate}
        \item Contrary to popular belief, Lorem Ipsum is ..
        \item Lorem Ipsum passages, and more recently
        \item Lorem Ipsum has been the industry
    \end{enumerate}
}

\end{document} 

```

This generates:

[![fancy box](https://i.stack.imgur.com/5Z0jS.png)](https://i.stack.imgur.com/5Z0jS.png)
An idea to start: 

```
\documentclass{article}
\usepackage{xcolor}
\begin{document}
{\color{magenta}
\parbox{.2\linewidth}{bla...}%
\hfill\vrule width 2pt }\hfill
\parbox[t]{.7\linewidth}{bla... }
\end{document}

```