\documentclass{letter}

\signature{\'Eric Larour}
\address{Jet Propulsion Laboratory\\4800 Oak Grove Drive\\CA 91109 Pasadena}
\begin{document}

\begin{letter}{RECIPIENT\\ADRESS}
\opening{Dear RECIPIENT,}

BLABLABLA BLABLABLA BLABLABLA BLABLABLA BLABLABLA

\closing{regards,}
\end{letter}

\end{document}
