Model as shown in the image

Question

What code do I use to place this model as shown in the image? "April 2007" below the page. So it stays on every page of the document.

\documentclass[a4paper,12pt]{article} 
\usepackage[utf8]{inputenc}

\usepackage[lmargin=3cm,tmargin=3cm,rmargin=2cm,bmargin=2cm]{geometry}


\usepackage{fancyhdr} 
\usepackage{lipsum} 
\pagestyle{fancy}

\headheight=14pt

\lhead{Rareness} 
\rhead{problems} 
\thispagestyle{fancy}

\usepackage[onehalfspacing]{setspace} 
\usepackage[brazil]{babel} 
\usepackage{enumerate} 
\newcommand{\quest}[1]{ \vspace{.8cm} \noindent\textbf{Questão #1. } }

\usepackage{amsmath} 
\usepackage{graphicx}

\everymath{\displaystyle}

\begin{document} 

\newcommand{\opt}[2]{\begin{enumerate}[a) ]  \item #1 ....

Answer 1

Well, you need to use a package to set an header and footer. In your case you are already using such a package, called fancyhdr. There you can use

\lfoot{April 2007}

to define an left footer containing April 2007.

With the following TeX code

\documentclass[a4paper,12pt]{article} 

\usepackage[utf8]{inputenc}

\usepackage[lmargin=3cm,tmargin=3cm,rmargin=2cm,bmargin=2cm]{geometry}

\usepackage{fancyhdr} 
\pagestyle{fancy}

\headheight=14pt
\lhead{Rareness} 
\rhead{problems} 
\lfoot{April 2007} % <==================================================
\cfoot{} % <============================================== no pagenumber

\usepackage[onehalfspacing]{setspace} 
\usepackage[brazil]{babel} 
\usepackage{enumerate} 
\newcommand{\quest}[1]{ \vspace{.8cm} \noindent\textbf{Questão #1. } }

\usepackage{amsmath} 
\usepackage{graphicx}

\usepackage{blindtext} % <======================= to generate dummy text

\everymath{\displaystyle}


\begin{document} 
  \Blindtext % <================================= create dummy text here
\end{document}

you get the resulting pdf:

Answer 2

Is it good solution for You?

    \documentclass[a4paper,12pt]{article} 
    \usepackage[utf8]{inputenc}

    \usepackage[lmargin=3cm,tmargin=3cm,rmargin=2cm,bmargin=2cm]{geometry}


    \usepackage{fancyhdr} 
    \usepackage{lipsum} 
    \pagestyle{fancy}

    \headheight=14pt

    \lhead{Rareness} 
    \rhead{problems} 
    \thispagestyle{fancy}

    \usepackage[onehalfspacing]{setspace} 
    \usepackage[brazil]{babel} 
    \usepackage{enumerate} 
    \newcommand{\quest}[1]{ \vspace{.8cm} \noindent\textbf{Questão #1. } }

    \usepackage{amsmath} 
    \usepackage{graphicx}

    \everymath{\displaystyle}


    \usepackage{fancyhdr}      
    \fancypagestyle{myfancy}
    {
        \fancyhf{}
        \renewcommand{\headrulewidth}{0pt}
        \lfoot{\today}
        %\rfoot{\thepage/\pageref{LastPage}}
    }

       

    \pagestyle{myfancy}
    \geometry{left=3cm,right=3cm,top=1.6cm,bottom=3cm,headheight=0pt,headsep=10pt}
    \begin{document} 



    \lipsum[1-8]


    \end{document}