This is an unofficial latex letter template in Greek for the Cyprus University of Technology.
\documentclass[11pt,a4paper]{letter} % Specify the font size (10pt, 11pt and 12pt) and paper size (letterpaper, a4paper, etc)
\usepackage{graphicx} % Required for including pictures
\usepackage{microtype} % Improves typography
\usepackage{palatino}
\usepackage{xltxtra}
\usepackage{xgreek}
\usepackage{fontspec}
\usepackage{xunicode}
\setromanfont{FreeSerif}
\setsansfont{FreeSans}
\usepackage{lipsum}
% Create a new command for the horizontal rule in the document which allows thickness specification
\makeatletter
\def\vhrulefill#1{\leavevmode\leaders\hrule\@height#1\hfill \kern\z@}
\makeatother
% DOCUMENT MARGINS
\textwidth 6.75in
\textheight 8.5in
\oddsidemargin -.25in
\evensidemargin -.25in
\topmargin -0.5in
\longindentation 0.50\textwidth
\parindent 0.2in
% SENDER INFORMATION
\def\Who{Όνομα Επώνυμο} % Your name
\def\What{Δρ~} % Your title
\def\Where{Τμήμα Ηλεκτρολόγων Μηχανικών, Μηχανικών \\Ηλεκτρονικών Υπολογιστών \& Πληροφορικής} % Your department/institution
\def\Address{Τεχνολογικό Πανεπιστήμιο Κύπρου} % Your address
\def\CityZip{Λεμεσός, Κύπρος} % Your city, zip code, country, etc
\def\Email{E-mail: x.y@cut.ac.cy} % Your email address
\def\TEL{Τηλ: +357 25 123456} % Your phone number
\def\URL{Web: https://cut.ac.cy} % Your URL
% HEADER AND FROM ADDRESS STRUCTURE
\address{
\vspace*{-1.3in}\includegraphics[height=0.9in]{CUT_logo.png}\hspace{-4.0in}~\\ % Include the logo of your institution
%\raggedleft Electric Power Systems and Applications \\
\vhrulefill{1pt} \\
\hspace{\fill}\parbox[t]{3.48in}{ % Create a box for your details underneath the horizontal rule on the right
\footnotesize % Use a smaller font size for the details
\textbf{\What \Who} \\ \em % Your name, all text after this will be italicized
\Where\\ % Your department
\Address\\ % Your address
\CityZip\\ % Your city and zip code
\TEL\\ % Your phone number
\Email\\ % Your email address
\URL % Your URL
}
\hspace{-1.1in} % Horizontal position of this block, increase to move left, decrease to move right
\vspace{-0.1in} % Move the letter content up for a more compact look
}
% TO ADDRESS STRUCTURE
\def\opening#1{\thispagestyle{empty}
{\centering\fromaddress \vspace{0.5in} \\ % Print the header and from address here, add whitespace to move date down
\hspace*{\fill}\today\par} % Print today's date, remove \today to not display it
{\raggedright \toname \\ \toaddress \par} % Print the to name and address
\vspace{0.4in} % White space after the to address
\noindent #1 % Print the opening line
% Uncomment the 4 lines below to print a footnote with custom text
%\def\thefootnote{}
%\def\footnoterule{\hrule}
%\footnotetext{\hspace*{\fill}{\footnotesize\em Footnote text}}
%\def\thefootnote{\arabic{footnote}}
}
% SIGNATURE STRUCTURE
\signature{\What \Who \\Λέκτορας} % The signature is a combination of your name and title
\long\def\closing#1{
\vspace{0.5in} % Some whitespace after the letter content and before the signature
\noindent % Stop paragraph indentation
\hspace*{5,2in} % Move the signature right
\parbox{\indentedwidth}{\raggedright
#1 % Print the signature text
~~\\ ~\includegraphics[width=3.0cm]{sig} \vspace{-1cm} % insert signature (remove if you are going to print and sign)
\vskip 0.5in % Whitespace between the signature text and your name
\fromsig}} % Print your name and title
\begin{document}
% TO ADDRESS
\begin{letter}
{\textbf{Κύριο Όνομα Επώνυμο Παραλήπτη}\\Τμήμα}
% LETTER CONTENT
\opening{Κύριε Παραλήπτη,}
\lipsum[1-6]
\vspace{-0,5cm}
\closing{Με εκτίμηση,}
\end{letter}
\end{document}