On Sunday, 12 Nov 2017 at 14:34, Mohamed Zaki wrote:
> Hi
>
> I am trying to export an org file to latex using the org-mode version
> 9.1.2. The input file structure is:

You could try:

    #+LaTeX_CLASS: LTR
    #+options: toc:nil
    #+attr_latex: :options {To somebody \\ Somewhere \\ Planet Earth}
    #+begin_letter 
    \opening{Dear Sir/Madam,}
    Some text
    \closing{Thank you,}

    #+end_letter

but note that the entry you have defined for the LTR org latex class is
incorrect as it is not intended for defining blocks.  So long as you
don't use any headings, the above will work (or does for me).

In any case, I would recommend using ox-koma-letter instead...

-- 
: Eric S Fraga via Emacs 27.0.50, Org release_9.1.2-155-gf474c7