//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 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");
        }