% Graph paper A4 21 x 29.7 cm
% This code will draw lines 28pt apart from edge to edge, with 2cm trimmed from both sides of A4 paper

\documentclass{article}
\usepackage[paperheight=124pt, paperwidth=17cm]{geometry}
\usepackage{tikz}
\pagestyle{empty}
 
\begin{document}
\begin{tikzpicture}[remember picture,overlay]
    \foreach \y in {28, 56, 84, 112}
        \draw[black,line width=0.5pt] (current page.north west) ++(0cm,-\y pt) -- ++(\paperwidth-0cm,0);
\end{tikzpicture}
\end{document}