One option is to use the background package; a little example in which I placed the text in italics below the upper rule of the frame (of course, you can easily change the position and attributes of the elements according to your needs):
\documentclass{article}
\usepackage{background}
\usepackage{lipsum}
\backgroundsetup{
scale=1,
angle=0,
opacity=1,
color=black,
contents={\begin{tikzpicture}[remember picture,overlay]
\draw ([xshift=1in,yshift=1in]current page.south west) rectangle ([xshift=-1in,yshift=-1in]current page.north east);
\node at ([yshift=-1.2in]current page.north)
{\itshape Proprietary information of company XYZ, do not redistribute without express consent};
\end{tikzpicture}}
}
\begin{document}
\lipsum[1-20]
\end{document}
An image of the first two pages:
and a zommed image of the topportin of one of the pages:
Using the old syntax of the package (if the newest version is not available), one has to say
\SetBgScale{1}
\SetBgAngle{0}
\SetBgOpacity{1}
\SetBgColor{black}
\SetBgContents{\begin{tikzpicture}[remember picture,overlay]
\draw ([xshift=1in,yshift=1in]current page.south west) rectangle ([xshift=-1in,yshift=-1in]current page.north east);
\node at ([yshift=-1.2in]current page.north)
{\itshape Proprietary information of company XYZ, do not redistribute without express consent}; \end{tikzpicture}}
Replacing
\node at ([yshift=-1.2in]current page.north)
{\itshape Proprietary information of company XYZ, do not redistribute without express consent};
with
\node at ([yshift=0.5in]current page.south)
{\itshape Proprietary information of company XYZ, do not redistribute without express consent};
one gets the legend at the bottom, outside the frame, as the following image shows:
