Write a letter right below mdframed

Question

is there a way to write something just right below an mdframed-box?

MWE:

\documentclass[a4paper]{article}
\usepackage{mdframed}
\begin{document}
\begin{mdframed}[leftmargin=5mm, rightmargin=5mm]
    Text of the full space of the mdframed. Just tried to fit the space fully.
\end{mdframed}
\end{document}

Next I will add the output with an added red letter:

I want to add a letter or a symbol (square, triangle, circle, whatever) directly in that corner. Is there an easy way to do so?

Answer 1

If you want to put the letter at the end of the line, just use \hfill to set the letter at the end of the line

\documentclass{article}
\pagestyle{empty}
\usepackage{mdframed, color}
\begin{document}
\begin{mdframed}[leftmargin=5mm, rightmargin=5mm]
    Text of the full space of the mdframed. Just tried to fit the
    space fully. \hfill\textcolor{red}{S}
\end{mdframed}
\end{document}

If you want to move the letter further down and right, use \rlap and \raisebox judiciously, like this:

\documentclass{article}
\pagestyle{empty}
\usepackage{mdframed, color}
\begin{document}
\begin{mdframed}[leftmargin=5mm, rightmargin=5mm]
    Text of the full space of the mdframed. Just tried to fit the
    space fully. 
    \hfill\rlap{\raisebox{-\fboxsep}[0pt][0pt]{\hspace{\fboxsep}\textcolor{red}{S}}}
\end{mdframed}
\end{document}