Since such can be unlocked, screenshot or other the answer is simply no. There are sites that tamper with product manuals and frankly they are treading in deep water as they don't own the manual or copyright. Let's let them take the chance?
Im running a site on wordpress and If Someone uploads a file (PDF, Word, PNG etc) once it has been uploaded and the watermark has been applied that the file can be opened and viewed but not altered in any way. In other words, it's kind of locked.
Can some one suggest me any plugin ?