\documentclass[12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[greek,english]{babel}
\usepackage{alphabeta}
\author {Afroditi Resta}
\title {My first title}
\begin{document}
\maketitle 
\section {My first section}
\par My first paragraph 
\subsection {My first subsection}
\begin {center}
         ``LaTeX is a document preparation system and document markup language. LaTex uses the TeX typesetting program for formatting its
         output, and is \\ itself written in the TeX macro language.΄΄\\
         LaTeX is not the name of a particular editing program, but \\
         refers to the encoding or tagging conventions that are used in LaTeX documents.
\end {center}

Εδώ γράφω Ελληνικά
\end{document}         
