If you want to share a protected PDF that only registered users can open, you need more than a watermark. You also need to make sure the PDF checks the user’s login before it opens. This article shows a simple
Does enabling iOS and Android access reduce PDF DRM protection in secure online PDF reading?
Many people worry about this when they start using online PDF protection tools: “If I allow mobile access, will my protected PDF become easier to copy or leak?” This is a common concern, especially for eBook sellers, teachers, and companies