\documentclass{article}

\usepackage{extarrows,amsmath}


\usepackage{xepersian}
\makeatletter
\@ifundefined{Umathcode}{\let\Umathcode\XeTeXmathcode}{}
\@ifundefined{Umathchardef}{\let\Umathchardef\XeTeXmathchardef}{}
\makeatother

\begin{document}

\begin{align}
\xlongequal[sub-script]{super-script}\\[1mm]
\xLongleftarrow[sub-script]{super-script}\\[1mm]
\xLongrightarrow[sub-script]{super-script}\\[1mm]
\xLongleftrightarrow[sub-script]{super-script}\\[1mm]
\xLeftrightarrow[sub-script]{super-script}\\[1mm]
\xlongleftrightarrow[sub-script]{super-script}\\[1mm]
\xlongrightarrow[sub-script]{super-script}\\[1mm]
\xleftrightarrow[sub-script]{super-script}\\[1mm]
\xlongleftarrow[sub-script]{super-script}\\[1mm]
\xleftarrow[sub-script]{super-script}\\[1mm]
\xrightarrow[sub-script]{super-script}\\[1mm]
\xlongleftarrow[sub-script]{super-script}\\[1mm]
\xlongrightarrow[sub-script]{super-script}\\[1mm]
\xleftarrow[sub-script]{super-script}\\[1mm]
\xrightarrow[sub-script]{super-script}\\[1mm]
\end{align}
\end{document}