\documentclass[a4paper, oneside, spanish]{article}
\usepackage[aztec]{qrgrader}
\qrgraderpagestyle{Subject name or exam title}

\begin{document}

    \IDMatrix{0.6cm}{\uniqueid}{Student ID figure}

    \begin{exam}[shuffle=off, style=matrix, showcorrect=no, encode=yes]

        \question[score=0.5, penalty=0.125, brief=first]{1}
        {Stem 1}
%%
        {Key}
%%
        {Distractor 1}
%%
        {Distractor 2}
%%
        {Distractor 3}
%%
        \question[score=0.5, penalty=0.125, brief=second, style=horizontal]{2}
        {Stem 2}
%%
        {Key}
%%
        {Distractor 1}
%%
        {Distractor 2}
%%
        {Distractor 3}
%
        \question[score=0.5, penalty=0.125, brief=third, style=list]{3}
        {Stem 3}
%%
        {Key}
%%
        {Distractor 1}
%%
        {Distractor 2}
%%
        {Distractor 3}

        \question[score=0.5, penalty=0.125, brief=fourth, style=list]{4}
        {Stem 4}
%%
        {Key}
%%
        {Distractor 1}
%%
        {Distractor 2}
%%
        {Distractor 3}

        \develquestion[score=1]{5}{
            \textbf{Open question}
        }
        {
            Stem of the open question
        }

    \end{exam}
\end{document}