I would insert it as a watermark. To print a watermark, you must insert it into a header or footer. The watermark is printed wherever you place it on the page and it doesn't have to be confined to the area at the top or bottom of the page.
1 On the View menu, click Header and Footer.
2 On the Header and Footer toolbar, click Show/Hide Document Text to hide the text and graphics in the main document.
3 Insert a graphic - a drawing object such as an AutoShape, clip art, WordArt, pictures, and imported art that appears on every page.
4 To format the graphic, select it, and then click Picture or Object (Format menu). On the Picture tab, under Image control, select Watermark from the Color box to format the picture with preset brightness and contrast settings that work well for watermarks, or adjust the picture's brightness and contrast manually using the Brightness and Contrast slide controls. To format the graphic so that document text flows above it instead of wrapping around it, click Picture or Object (Format menu). On the Wrapping tab, click None.
To format the text in the text box, select it, click Font on the Format menu, and then select the options you want. To rotate the text, click Text Direction on the Format menu, and then select the option you want. Because the text box is a drawing object, you can use options on the Drawing toolbar to format its borders, background color, and so on.
5 On the Header and Footer toolbar, click Close.
Notes
* To view a watermark as it will appear on the printed page, switch to page layout view or print preview.
* If the watermark interferes with the legibility of the text on the page, you can lighten the object you used to create the watermark.