Il suffit de lire la doc : texdoc datetime2 !
\documentclass[a4paper,french]{scrartcl}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
%% Format de date
\usepackage[useregional,showdow]{datetime2} % showdow : date longue
\begin{document}
\Today
\end{document}