\documentclass[12pt]{article}
\usepackage[arabmaths]{luabidi}
\begin{document}
\setRTLmain
\section{ghesmate 1}

in yek ghesmat ast ke an ra dar inja minevisam

\begin{equation}
1+2=3
\end{equation}
in ham dobare masalei ast ke man minevisam va shoma an ra mibinid.
\end{document}