Change figures numbering in Latex

Question

Is there any way to change the numbering of figures in Latex?

For example it starts the figure as:

Figure 01: Legend

I would like it to be in this format starting in 2.1

Figure 2.1: Legend

Answer 1

I assume that 2.1 is Figure 1 of Section 2...

In that case, in the preamble, we join:

\usepackage{amsmath}
\numberwithin{figure}{section}

For the numbering of figures to include the section number (adapt as desired)

Minimalist example:

\documentclass{article}
\usepackage{graphicx}
\usepackage{amsmath}
\numberwithin{figure}{section}

\begin{document}
\section{Primeira sec.}

\section{Segunda sec.}

\begin{figure}[h]
  \centering
    \fbox{Substituir pela Imagem A}
    \caption{figura A}
\end{figure}
\end{document}