change subfigure configuration in latex

I use the following example code to create a subfigure in my latex document.

\usepackage{caption}
\usepackage{subcaption}

\begin{figure}
 \centering
 \begin{subfigure}[b]{0.3\textwidth}
     \centering
     \includegraphics[width=\textwidth]{Figures/F1.png}
     \caption{}
     \label{fig:1}
 \end{subfigure}
 \hfill
 \begin{subfigure}[b]{0.3\textwidth}
     \centering
     \includegraphics[width=\textwidth]{Figures/F2.png}
     \caption{}
     \label{fig:2}
 \end{subfigure}
 \hfill
 \begin{subfigure}[b]{0.3\textwidth}
     \centering
     \includegraphics[width=\textwidth]{Figures/F3.png}
     \caption{}
     \label{fig:3}
 \end{subfigure}
    \caption{Values}
    \label{fig:three graphs}
\end{figure}

And I get the following output configuration

But the sub-figures are too small on the page. So I want to change it to the following configuration and make the figure a bit larger and centered. How to modify this code to change the Figure configuration?

\documentclass{article}

\usepackage{caption}
\usepackage{subcaption}
\usepackage{graphicx}

\begin{document}

\begin{figure}
 \centering
 \begin{subfigure}[b]{0.45\textwidth}
     \centering
     \includegraphics[width=\textwidth]{example-image-duck}
     \caption{}
     \label{fig:1}
 \end{subfigure}
 \quad
 \begin{subfigure}[b]{0.45\textwidth}
     \centering
     \includegraphics[width=\textwidth]{example-image-duck}
     \caption{}
     \label{fig:2}
 \end{subfigure}
 
 \begin{subfigure}[b]{0.45\textwidth}
     \centering
     \includegraphics[width=\textwidth]{example-image-duck}
     \caption{}
     \label{fig:3}
 \end{subfigure}
    \caption{Values}
    \label{fig:three graphs}
\end{figure}
\end{document}