\documentclass{article}
\usepackage{lipsum}
\usepackage{bidi-atbegshi}
\usepackage[RTLdocument]{bidi}
\setbox0\hbox{\Huge\textbf{Upper Left}}
\setbox1\hbox{\Huge\textbf{Upper Right}}
\setbox2\hbox{\Huge\textbf{Lower Left}}
\setbox3\hbox{\Huge\textbf{Lower Right}}
\AtBeginShipout{%
\AtBeginShipoutUpperRightForeground{%
\put(0,\LengthToUnit{-\ht1}){\usebox1}
}%
\AtBeginShipoutUpperLeftForeground{%
\put(\LengthToUnit{-\wd0},\LengthToUnit{-\ht0}){\usebox0}
}%
\AtBeginShipoutLowerRightForeground{%
\put(0,\LengthToUnit{\dp3}){\usebox3}
}%
\AtBeginShipoutLowerLeftForeground{%
\put(\LengthToUnit{-\wd2},\LengthToUnit{\dp2}){\usebox2}
}%
}
\begin{document}
\lipsum
\end{document}