I'm making a document with document class scrreprt, and used this to get the page numbering on the top of the pages, and a line on the top of the page
\documentclass[11pt, twoside=semi, titlepage]{scrreprt}
\usepackage[top=2.5cm, bottom=2.5cm, left=6cm, right=2cm, heightrounded,
marginparwidth=3.5cm, marginparsep=0.5cm]{geometry}
%% To make the marginnotes appear on the left side on all the pages
\usepackage[strict]{changepage}
\usepackage{etoolbox}
\makeatletter
\patchcmd{\@addmarginpar}{\ifodd\c@page}{\ifodd\c@page\@tempcnta\m@ne}{}{}
\makeatother
\reversemarginpar
\usepackage[automark, headsepline]{scrlayer-scrpage}
\clearpairofpagestyles
\lehead[\pagemark]{\pagemark}
\rohead[\pagemark]{\pagemark}
\chead{\headmark}
\chead{\headmark}
\usepackage{blindtext}
\begin{document}
\blinddocument
\end{document}
Is it possible to make the line longer, so its over both the text and the margin notes?



\setheadwidth{textwithmarginpar}– Johannes_B Oct 27 '14 at 17:12article; the suggested methods can be extended to the other standard classes, butscrreprtis a different animal. – egreg Oct 27 '14 at 17:20\documentclass{...}, the required\usepackage's,\begin{document}, and\end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. – Sverre Oct 27 '14 at 21:13