Watermark on image software has provide option to set stamp position on page like top, bottom, left, right and set in diagonally. You can set both text and image as stamp. Software has provide multiple feature like change image size, set font, set opacity, set position, etc. You can set stamp opacity by increasing and decreasing opacity. If you add this software or create more knowledge so, go this link www.pdfwatermarksoftware.com to add stamp.