//The value of this string is the watermark
        string watermark = "Classified";

 
      public void GenerateDocument()
        	{
            /*/ Create an instance of the WordApplication object
*/
            WordApplication wwApp = new WordApplication();

            /*/ Open the unclassified document */without  watermark
          Document doc = wwApp.Open(@"..\..\Templates/PreWatermark.doc");

            /*/ Set the watermark
*/
            doc.Watermark.Text = watermark;

            /*/ Save the document to the Response stream
*/
            wwApp.Save(doc, @"..\..\Output\Watermarked_out.doc");
        }