How to use Latex for awesome letters

$ sudo apt-get install texlive-full

% define a new A4 document with 12pt font size
\documentclass[a4paper,12pt]{article}

% define a new A4 document with 12pt font size
\documentclass[a4paper,12pt]{article}

% for mobile phone etc symbols
\usepackage{marvosym}

% set margins with no header and no footer
\usepackage[left=1.9cm,top=2cm,bottom=2.5cm,right=1.9cm,nohead,nofoot]{geometry}

% if fancy tables are needed
\usepackage{array}

% if colors are needed
\usepackage{color}

% Latex can't use TrueType fonts out of the box
% to use TrueType fonts, use this package. 
% Caveat: need to compile with XeLatex
\usepackage{fontspec}
\setmainfont{Linux Libertine O}

% no page numbers
\pagestyle{empty}

% for images and image files list of search paths
\usepackage{graphicx}
\graphicspath{{.}{../../../Photos/}}

% no paragraph identation (or change it to whatever is needed)
\setlength{\parindent}{0pt}

% space between paragraphs
\setlength{\parskip}{11pt}

% interline space
\linespread{1.125}

% PDF metadata into the final file
\usepackage[
            pdfauthor={Conan Doyle},
            pdftitle={Adventures of Sherlock Holmes}
            ]{hyperref}

\begin{document}
\end{document}

%% ------------------------------------------------------------
%% document start
%% ------------------------------------------------------------
\begin{document}

%% ------------------------------------------------------------
%% header table
%% ------------------------------------------------------------
\begin{tabular}{p{10cm} p{5cm}}

    \begin{minipage}[t]{0.40\textwidth}
        \begin{flushleft}
            {\Large \textbf{John H. Watson}}\\[10pt]
            221B Baker Street\\
            London\\[8pt]
            \Mobilefone ~ +41 06 00 00 00 00\\
            \Email ~ john.watson@outlook.com\\[20pt]
        \end{flushleft}
    \end{minipage}

    &

    \begin{minipage}[t]{0.40\textwidth}
        \begin{flushright}
            {\Large \textbf{Professor Moriarty}}\\[10pt]
            6649 N Blue Gum St\\
            London\\
        \end{flushright}
    \end{minipage}  

\end{tabular}



\begin{flushleft}
London, 1895

Object: A scandal in Bohemia
\end{flushleft}



\vspace{1.5cm}

%% ------------------------------------------------------------
%% Letter body
%% ------------------------------------------------------------
Dear Sir,
\vspace{1.5cm}

To Sherlock Holmes she is always the woman. I have seldom heard
him mention her under any other name. In his eyes she eclipses and
predominates the whole of her sex. It was not that he felt any emotion
akin to love for Irene Adler. All emotions, and that one particularly,
were abhorrent to his cold, precise, but admirably balanced mind. He
was, I take it, the most perfect reasoning and observing machine that
the world has seen; but, as a lover, he would have placed himself in a
false position. He never spoke of the softer passions, save with a gibe
and a sneer. 

They were admirable things for the observer—excellent
for drawing the veil from men’s motives and actions. But for the
trained reasoner to admit such intrusions into his own delicate and
finely adjusted temperament was to introduce a distracting factor which
might throw a doubt upon all his mental results. Grit in a sensitive
instrument, or a crack in one of his own high-power lenses, would not
be more disturbing than a strong emotion in a nature such as his. And
yet there was but one woman to him, and that woman was the late Irene
Adler, of dubious and questionable memory.

I had seen little of Holmes lately. My marriage had drifted us away
from each other. My own complete happiness, and the home-centred
interests which rise up around the man who first finds himself master
of his own establishment, were sufficient to absorb all my attention;
while Holmes, who loathed every form of society with his whole
Bohemian soul, remained in our lodgings in Baker Street, buried among
his old books, and alternating from week to week between cocaine and
ambition, the drowsiness of the drug, and the fierce energy of his
own keen nature.

\vspace{1cm}
\hspace{10cm} Sherlock Holmes

\end{document}