You can put it in the header or you can create a watermark.
To put it in the header go to View > Header/Footer and insert the required
text into the header. If you have different first page set up then you will
need to do this on the first page and on the second page of your document.
To insert a watermark, it depends which version of Word you have as to how
you do this.
Office XP/2003: go to Format > Background > Printed Watermark.
Click the Text watermark radio button and insert the required text and
formatting.
Click Apply and then OK.
Office 2000:
Check whether you have your page setup as different first page - if you do,
then you will have to do this twice, once on the first page and once on a
subsequent page.
Go to View Header / Footer
Click on the Show/Hide document text button
Go to Insert > Picture > WordArt and select the style you want for your
watermark, (usually one of the diagonal ones is best)
Type the text in that you want and click OK
RIght click the Word art and choose format wordart, go to the layout tab and
make sure it is set to behind text.
On the colors and lines tab, adjust the fill colour as desired.
Tweak the position and size if necessary by using the drag or resize handles.
Close header and footer view.
You should be able to see your watermark in print preview.
Genine