\documentclass[a4paper,landscape]{article}

\usepackage[landscape,top=1cm,left=1cm,bottom=1cm,right=3cm]{geometry}
\usepackage{tikz}
\usetikzlibrary{matrix}
\usetikzlibrary{backgrounds}
\usetikzlibrary{intersections}
\usetikzlibrary{positioning}
\usetikzlibrary{calc}

\pagestyle{empty}
\setlength{\parindent}{0cm}

\tikzset{outer/.style={remember picture,show background rectangle,tight background,background rectangle/.style={draw,ultra thick}}}

\newcommand{\checkbox}[1]{\tikz[label distance=0.2cm]{\node[label={east:\large{#1}},draw,very thick,rectangle,text height=0.5cm,text width=0.5cm,inner sep=0cm] at (0,0) {};}}
\newcommand{\emptycheckbox}{\tikz{\node[text height=0.5cm,text width=0.5cm,inner sep=0cm] at (0,0) {};}}

\begin{document} \sffamily
\begin{tikzpicture}[outer]
    \node[anchor=north west,align=center,text width=27cm] (header) at (0,0) {\textbf{TEILNEHMER - / INNENLISTE}};
    \matrix (options) at ($(header.south west)+(0.5cm,-1cm)$) [matrix of nodes, column sep=0cm,row sep=0.5cm,nodes in empty cells, every node/.style={inner sep=0cm,align=left,text width=6.2cm}, anchor=north west] {
        \checkbox{Jugendbildungsmaßnahme} & \checkbox{Gruppenleiter/innenschulung} & \checkbox{Ferienkolonie} & \checkbox{Freizeitnaßnahme} \\
        \checkbox{Int. Jugendbegegnung}   & \checkbox{politische Jugendbildung}    & \checkbox{Projekte}      & \emptycheckbox              \\
    };
    \node[align=left,inner sep=0cm,anchor=west] at (options-2-4.west) {\tikz{\node[draw,very thick,rectangle,text height=0.5cm,text width=0.5cm,inner sep=0cm] (checkbox) at (0,0) {}; \draw[thick] (checkbox.south east) ++(0.2cm,0) -- (checkbox.south east -| options-2-4.south east);}};

    \node[anchor=north west] (org) at ($(options.south west)+(0cm,-0.5cm)$) {\large{Veranstalter:}};
    \draw[thick] (org.south east -| options-2-2.south west) -- (org.south east -| options-2-4.south east) node[pos=0.02,above=0.1cm] {\LARGE{aa}};

    \node[anchor=north west] (title) at ($(org.south west)+(0cm,-0.5cm)$) {\large{Titel der Maßnahme:}};
    \draw[thick] (title.south east -| options-2-2.south west) -- (title.south east -| options-2-4.south east);

    \node[anchor=north west] (datefrom) at ($(title.south west)+(0cm,-0.5cm)$) {\large{Datum vom:}};
    \draw[thick] (datefrom.south east -| options-2-2.south west) -- ($(datefrom.south east -| options-2-2.south east) - (1,0cm)$);

    \node[anchor=south west] (dateuntil) at (options-2-3.south west |- datefrom.south west) {\large{bis:}};
    \draw[thick,label={east:aaa}] (dateuntil.south east) -- (datefrom.south east -| options-2-3.south east);

    \path[fill=yellow] (datefrom.south -| 0,0) ++(0,-1.5cm) rectangle ++(27,0.4cm);

    \draw (datefrom.south) -- ++(4cm,-4cm);

\end{tikzpicture}

% \pagebreak[4]
% 
% \begin{tikzpicture}[outer]
%     \node[align=center,text width=27cm] (header) at (0,0) {\textbf{TEILNEHMER - / INNENLISTE}};
%     \matrix (options) at ($(header.south west)+(0.5cm,-1cm)$) [matrix of nodes, column sep=0cm,row sep=0.5cm,nodes in empty cells, every node/.style={inner sep=0cm,align=left,text width=6.2cm}, anchor=north west] {
%         \checkbox{Jugendbildungsmaßnahme} & \checkbox{Gruppenleiter/innenschulung} & \checkbox{Ferienkolonie} & \checkbox{Freizeitnaßnahme} \\
%         \checkbox{Int. Jugendbegegnung}   & \checkbox{politische Jugendbildung}    & \checkbox{Projekte}      & \emptycheckbox              \\
%     };
%     \node[align=left,inner sep=0cm,anchor=west] at (options-2-4.west) {\tikz{\node[draw,very thick,rectangle,text height=0.5cm,text width=0.5cm,inner sep=0cm] (checkbox) at (0,0) {}; \draw[thick] (checkbox.south east) ++(0.2cm,0) -- (checkbox.south east -| options-2-4.south east);}};
% 
%     \node[anchor=north west] (org) at ($(options.south west)+(0cm,-0.5cm)$) {\large{Veranstalter:}};
%     \draw[thick] (org.south east -| options-2-2.south west) -- (org.south east -| options-2-4.south east) node[pos=0.02,above=0.1cm] {\LARGE{aa}};
% 
%     \node[anchor=north west] (title) at ($(org.south west)+(0cm,-0.5cm)$) {\large{Titel der Maßnahme:}};
%     \draw[thick] (title.south east -| options-2-2.south west) -- (title.south east -| options-2-4.south east);
% 
%     \node[anchor=north west] (datefrom) at ($(title.south west)+(0cm,-0.5cm)$) {\large{Datum vom:}};
%     \draw[thick] (datefrom.south east -| options-2-2.south west) -- ($(datefrom.south east -| options-2-2.south east) - (1,0cm)$);
% 
%     \node[anchor=south west] (dateuntil) at (options-2-3.south west |- datefrom.south west) {\large{bis:}};
%     \draw[thick,label={east:aaa}] (dateuntil.south east) -- (datefrom.south east -| options-2-3.south east);
% 
%     \fill[yellow] (0,0) rectangle ($(current page.east) + (0,-1cm)$);
% 
%     \draw (datefrom.south) -- ++(2cm,-2cm);
% 
% \end{tikzpicture}

\end{document}