\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}
\begin{document}
\section{Simple figures}
\label{sec:simple}

This is a simple figure; see \figurename{} \ref{fig:fig-example}.
\begin{figure}[!htb]
  \centering
  \includegraphics[width=3.5in]{example-image-a}
  \caption{Figure's caption.}
  \label{fig:fig-example}
\end{figure}
\end{document}