title: How to change the font size of my Latex document
body: <p>I found this latex template that has no font-size attribute, but the writing is just too small to be read.
  Hope you can help me figuring out how to change the font size, the template has a file called arxiv.sty that contains:</p>
  <pre><code>\NeedsTeXFormat{LaTeX2e}
  
  \ProcessOptions\relax
  
  % fonts
  \renewcommand{\rmdefault}{ptm}
  \renewcommand{\sfdefault}{phv}
  
  % set page geometry
  \usepackage[verbose=true,letterpaper]{geometry}
  \AtBeginDocument{
    \newgeometry{
      textheight=9in,
      textwidth=6.5in,
      top=1in,
      headheight=14pt,
      headsep=25pt,
      footskip=30pt
    }
  }
  
  \widowpenalty=10000
  \clubpenalty=10000
  \flushbottom
  \sloppy
  
  \usepackage{fancyhdr}
  \fancyhf{}
  \pagestyle{fancy}
  \renewcommand{\headrulewidth}{0pt}
  \fancyheadoffset{0pt}
  \rhead{\scshape \today}
  \cfoot{\thepage}
  
  
  %Handling Keywords
  \def\keywordname{{\bfseries \emph Keywords}}%
  \def\keywords#1{\par\addvspace\medskipamount{\rightskip=0pt plus1cm
  \def\and{\ifhmode\unskip\nobreak\fi\ $\cdot$
  }\noindent\keywordname\enspace\ignorespaces#1\par}}
  
  % font sizes with reduced leading
  \renewcommand{\normalsize}{%
    \@setfontsize\normalsize\@xpt\@xipt
    \abovedisplayskip      7\p@ \@plus 2\p@ \@minus 5\p@
    \abovedisplayshortskip \z@ \@plus 3\p@
    \belowdisplayskip      \abovedisplayskip
    \belowdisplayshortskip 4\p@ \@plus 3\p@ \@minus 3\p@
  }
  \normalsize
  \renewcommand{\small}{%
    \@setfontsize\small\@ixpt\@xpt
    \abovedisplayskip      6\p@ \@plus 1.5\p@ \@minus 4\p@
    \abovedisplayshortskip \z@  \@plus 2\p@
    \belowdisplayskip      \abovedisplayskip
    \belowdisplayshortskip 3\p@ \@plus 2\p@   \@minus 2\p@
  }
  \renewcommand{\footnotesize}{\@setfontsize\footnotesize\@ixpt\@xpt}
  \renewcommand{\scriptsize}{\@setfontsize\scriptsize\@viipt\@viiipt}
  \renewcommand{\tiny}{\@setfontsize\tiny\@vipt\@viipt}
  \renewcommand{\large}{\@setfontsize\large\@xiipt{14}}
  \renewcommand{\Large}{\@setfontsize\Large\@xivpt{16}}
  \renewcommand{\LARGE}{\@setfontsize\LARGE\@xviipt{20}}
  \renewcommand{\huge}{\@setfontsize\huge\@xxpt{23}}
  \renewcommand{\Huge}{\@setfontsize\Huge\@xxvpt{28}}
  
  % sections with less space
  \providecommand{\section}{}
  \renewcommand{\section}{%
    \@startsection{section}{1}{\z@}%
                  {-2.0ex \@plus -0.5ex \@minus -0.2ex}%
                  { 1.5ex \@plus  0.3ex \@minus  0.2ex}%
                  {\large\bf\raggedright}%
  }
  \providecommand{\subsection}{}
  \renewcommand{\subsection}{%
    \@startsection{subsection}{2}{\z@}%
                  {-1.8ex \@plus -0.5ex \@minus -0.2ex}%
                  { 0.8ex \@plus  0.2ex}%
                  {\normalsize\bf\raggedright}%
  }
  \providecommand{\subsubsection}{}
  \renewcommand{\subsubsection}{%
    \@startsection{subsubsection}{3}{\z@}%
                  {-1.5ex \@plus -0.5ex \@minus -0.2ex}%
                  { 0.5ex \@plus  0.2ex}%
                  {\normalsize\bf\raggedright}%
  }
  \providecommand{\paragraph}{}
  \renewcommand{\paragraph}{%
    \@startsection{paragraph}{4}{\z@}%
                  {1.5ex \@plus 0.5ex \@minus 0.2ex}%
                  {-1em}%
                  {\normalsize\bf}%
  }
  \providecommand{\subparagraph}{}
  \renewcommand{\subparagraph}{%
    \@startsection{subparagraph}{5}{\z@}%
                  {1.5ex \@plus 0.5ex \@minus 0.2ex}%
                  {-1em}%
                  {\normalsize\bf}%
  }
  \providecommand{\subsubsubsection}{}
  \renewcommand{\subsubsubsection}{%
    \vskip5pt{\noindent\normalsize\rm\raggedright}%
  }
  
  % float placement
  \renewcommand{\topfraction      }{0.85}
  \renewcommand{\bottomfraction   }{0.4}
  \renewcommand{\textfraction     }{0.1}
  \renewcommand{\floatpagefraction}{0.7}
  
  \newlength{\@abovecaptionskip}\setlength{\@abovecaptionskip}{7\p@}
  \newlength{\@belowcaptionskip}\setlength{\@belowcaptionskip}{\z@}
  
  \setlength{\abovecaptionskip}{\@abovecaptionskip}
  \setlength{\belowcaptionskip}{\@belowcaptionskip}
  
  % swap above/belowcaptionskip lengths for tables
  \renewenvironment{table}
    {\setlength{\abovecaptionskip}{\@belowcaptionskip}%
     \setlength{\belowcaptionskip}{\@abovecaptionskip}%
     \@float{table}}
    {\end@float}
  
  % footnote formatting
  \setlength{\footnotesep }{6.65\p@}
  \setlength{\skip\footins}{9\p@ \@plus 4\p@ \@minus 2\p@}
  \renewcommand{\footnoterule}{\kern-3\p@ \hrule width 12pc \kern 2.6\p@}
  \setcounter{footnote}{0}
  
  % paragraph formatting
  \setlength{\parindent}{\z@}
  \setlength{\parskip  }{5.5\p@}
  
  % list formatting
  \setlength{\topsep       }{4\p@ \@plus 1\p@   \@minus 2\p@}
  \setlength{\partopsep    }{1\p@ \@plus 0.5\p@ \@minus 0.5\p@}
  \setlength{\itemsep      }{2\p@ \@plus 1\p@   \@minus 0.5\p@}
  \setlength{\parsep       }{2\p@ \@plus 1\p@   \@minus 0.5\p@}
  \setlength{\leftmargin   }{3pc}
  \setlength{\leftmargini  }{\leftmargin}
  \setlength{\leftmarginii }{2em}
  \setlength{\leftmarginiii}{1.5em}
  \setlength{\leftmarginiv }{1.0em}
  \setlength{\leftmarginv  }{0.5em}
  \def\@listi  {\leftmargin\leftmargini}
  \def\@listii {\leftmargin\leftmarginii
                \labelwidth\leftmarginii
                \advance\labelwidth-\labelsep
                \topsep  2\p@ \@plus 1\p@    \@minus 0.5\p@
                \parsep  1\p@ \@plus 0.5\p@ \@minus 0.5\p@
                \itemsep \parsep}
  \def\@listiii{\leftmargin\leftmarginiii
                \labelwidth\leftmarginiii
                \advance\labelwidth-\labelsep
                \topsep    1\p@ \@plus 0.5\p@ \@minus 0.5\p@
                \parsep    \z@
                \partopsep 0.5\p@ \@plus 0\p@ \@minus 0.5\p@
                \itemsep \topsep}
  \def\@listiv {\leftmargin\leftmarginiv
                \labelwidth\leftmarginiv
                \advance\labelwidth-\labelsep}
  \def\@listv  {\leftmargin\leftmarginv
                \labelwidth\leftmarginv
                \advance\labelwidth-\labelsep}
  \def\@listvi {\leftmargin\leftmarginvi
                \labelwidth\leftmarginvi
                \advance\labelwidth-\labelsep}
  
  % create title
  \providecommand{\maketitle}{}
  \renewcommand{\maketitle}{%
    \par
    \begingroup
      \renewcommand{\thefootnote}{\fnsymbol{footnote}}
      % for perfect author name centering
      \renewcommand{\@makefnmark}{\hbox to \z@{$^{\@thefnmark}$\hss}}
      % The footnote-mark was overlapping the footnote-text,
      % added the following to fix this problem               (MK)
      \long\def\@makefntext##1{%
        \parindent 1em\noindent
        \hbox to 1.8em{\hss $\m@th ^{\@thefnmark}$}##1
      }
      \thispagestyle{empty}
      \@maketitle
      \@thanks
      %\@notice
    \endgroup
    \let\maketitle\relax
    \let\thanks\relax
  }
  
  % rules for title box at top of first page
  \newcommand{\@toptitlebar}{
    \hrule height 2\p@
    \vskip 0.25in
    \vskip -\parskip%
  }
  \newcommand{\@bottomtitlebar}{
    \vskip 0.29in
    \vskip -\parskip
    \hrule height 2\p@
    \vskip 0.09in%
  }
  
  % create title (includes both anonymized and non-anonymized versions)
  \providecommand{\@maketitle}{}
  \renewcommand{\@maketitle}{%
    \vbox{%
      \hsize\textwidth
      \linewidth\hsize
      \vskip 0.1in
      \@toptitlebar
      \centering
      {\LARGE\sc \@title\par}
      \@bottomtitlebar
      \textsc{}\\
      \vskip 0.1in
      \def\And{%
        \end{tabular}\hfil\linebreak[0]\hfil%
        \begin{tabular}[t]{c}\bf\rule{\z@}{24\p@}\ignorespaces%
      }
      \def\AND{%
        \end{tabular}\hfil\linebreak[4]\hfil%
        \begin{tabular}[t]{c}\bf\rule{\z@}{24\p@}\ignorespaces%
      }
      \begin{tabular}[t]{c}\bf\rule{\z@}{24\p@}\@author\end{tabular}%
    \vskip 0.4in \@minus 0.1in \center{\today}   \vskip 0.2in
    }
  }
  
  % add conference notice to bottom of first page
  \newcommand{\ftype@noticebox}{8}
  \newcommand{\@notice}{%
    % give a bit of extra room back to authors on first page
    \enlargethispage{2\baselineskip}%
    \@float{noticebox}[b]%
      \footnotesize\@noticestring%
    \end@float%
  }
  
  % abstract styling
  \renewenvironment{abstract}
  {
    \centerline
    {\large \bfseries \scshape Abstract}
    \begin{quote}
  }
  {
    \end{quote}
  }
  
  \endinput
  </code></pre>
  <p>and the template.tex file that contains the code below but no attributes telling about the font-size:</p>
  <pre><code>\documentclass{article}
  \usepackage{float}
  \usepackage{arxiv}
  \usepackage{graphicx}
  \usepackage[utf8]{inputenc} % allow utf-8 input
  \usepackage[T1]{fontenc}    % use 8-bit T1 fonts
  \usepackage{hyperref}       % hyperlinks
  \usepackage{url}            % simple URL typesetting
  \usepackage{booktabs}       % professional-quality tables
  \usepackage{amsfonts}       % blackboard math symbols
  \usepackage{nicefrac}       % compact symbols for 1/2, etc.
  \usepackage{microtype}      % microtypography
  \usepackage{lipsum}
  
  \title{
  </code></pre>