\documentclass[12pt]{article}
% options include 12pt or 11pt or 10pt
% classes include article, report, book, letter, thesis
\title{Enter the Title}
\author{1st Author \\ 2nd Author}
\date{today}
\begin{document}
\maketitle
This is the content of this document.
This is the 2nd paragraph.
Here is an inline formula:
% you need a numbered equation
\begin{equation}
A = \frac{4 \pi r^3}{3}
\end{equation}
And appearing immediately below
is a displayed formula:
$ B = \frac{4 \pi r^3}{3} $
\end{document}
