\documentclass[a4paper]{report}
\usepackage[top=2cm, bottom=2cm, left=3cm, right=3cm,includehead=true,includefoot=true]{geometry}
\renewcommand*{\baselinestretch}{1.15}
\usepackage[extrafootnotefeatures]{xepersian}
\settextfont{B Nazanin}
\begin{document}
\chapter{مقدمه}
مقدمه\\
\\
{\large\bf مفاهیم اصلی} 
\vspace*{2mm}
\begin{description}
\item[نقطه ممان صفر(\lr{ZMP})\LTRfootnote{Zero Moment Point}:] 

	
\end{description}
\end{document}