Digital deliverypany SendOwl offers PDF stamping. The default is to include the buyer name email address and order ID (and theyll do this 3 you don't have to input data manually). However you can choose what information about your buyer that you wish to include. You can choose how you style this buyer information 3 font font size font colour and so on 3 to make sure that it matches the style of your PDF. PDFs are also encrypted and a random password added once stamping isplete for extra protection against copying. This won't affect how your PDF looks or the reader experience. They currently only offer PDF stamping although are looking into stamping for other content such as epubs. More here PDF stamping for ebook security updated May 217 Deter would-be copiers without penalising your loyal customers s