\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{geometry}
\usepackage{xcolor}
\usepackage{tikz}
\usepackage{amssymb}
\usepackage{enumitem}
\usepackage{setspace}
\usepackage{helvet}
\renewcommand{\familydefault}{\sfdefault} % Sans-serif font for modern look

\geometry{top=2.5cm, bottom=2.5cm, left=2.5cm, right=2.5cm}

\definecolor{maincolor}{RGB}{40,60,90}
\definecolor{accentcolor}{RGB}{0,130,200}
\definecolor{lightgray}{gray}{0.9}

\begin{document}
\thispagestyle{empty}

% Background box
\begin{tikzpicture}[remember picture, overlay]
    \fill[maincolor] (current page.north west) rectangle ([xshift=6cm]current page.south west);
\end{tikzpicture}

% Reiseinformationen
\vspace*{2cm}
\begin{flushright}
    \color{maincolor}
    {\Huge \textbf{Reisemappe}}\\[0.5cm]
    {\LARGE \textbf{\textcolor{accentcolor}{DESTINATION}}}\\[1cm]
    {\Large \textbf{DATE}}\\[1cm]
    {\large \textbf{Name:} \textcolor{accentcolor}{PERSON}}\\
\end{flushright}

\vfill

% Checkliste
\begin{flushright}
    \color{maincolor}
    {\Large \textbf{Inhalt}}\\[0.5cm]
    \begin{minipage}{10cm}
        \color{black}
        \setlist[itemize]{label=$\square$, left=0pt}
        \begin{itemize}
            \item Reisebriefing
            \item Hotelbuchung
            \item Flugbuchungen
            \item Reisepass & Dokumente
        \end{itemize}
    \end{minipage}
\end{flushright}

\end{document}