\documentclass[foldmarks=true,foldmarks=blmtP,
  fromalign=center,fromrule=aftername,
  version=last]{scrlttr2}
\usepackage[british]{babel}
\begin{document}
\setkomavar{fromname}{Joe Public}
\setkomavar{fromaddress}{2 Valley\\
                         SAMPLEBY\\
                         ZY32 1XW}
\begin{letter}{%
    Joanna Public\\
    1 Hillside\\
    SAMPLESTEAD\\
    WX12 3YZ%
  }
\opening{Dear Madam Chair,}
The last general meeting was more than a year ago.
I would like to remind you that the articles of our
club stipulate that one should be held every
six months. For this reason, I call on the executive
board to arrange such a meeting immediately.
\closing{Anticipating an invitation}
\ps PS: I hope you do not take this request amiss.
\setkomavar*{enclseparator}{Enclosure}
\encl{Excerpt from the articles governing general
  meetings}
\cc{executive board\\all members}
\end{letter}
\end{document}
