Watermark On Pdf can add watermarks to all or some pages of a PDF file. If you then secure the document with a password to prevent changes, it can't be removed
The only solution (other than creating and removing the watermark) is to not share the file. Also, since PDFs are protected with a watermark, you are prohibited from printing them from your computer. But if you're sharing one, you can't alter it once it's gone (other users will now be able to see it), so it may not have much practical value to you. So you can think about a password-protecting PDF, which you then transfer to a friend. No one else can see the watermark, but everyone who accesses it knows it's yours (unless they know your password). It's not a great solution to have a public PDF. Even though you can be sure most people won't be able to get it, you still won't be able to use it. If you need it for business reasons, make sure someone you trust does the deed, not you. You may have to do this.