\documentclass{article}
\usepackage[extrafootnotefeatures]{xepersian}
\settextfont{Yas}
\makeatletter
\def\@makeLTRfnmark{\hbox{\@textsuperscript{\latinfont\@thefnmark}}}
\renewcommand\@makefntext[1]{%
    \parindent 1em%
    \noindent
    \hb@xt@1.8em{\hss\if@RTL\@makefnmark\else\@makeLTRfnmark\fi}#1}
\makeatother
\begin{document}
\threecolumnfootnotes


\footnote{آزمایش}\LTRfootnote{This is a test.}
\end{document}