I would like to know what is the feature or software in Acrobat which allows to indicate a licence with the name of the person who purchase the document and the utilisation conditions in the bottom of each page of the document ?
There is no such feature in Acrobat. You can add a security policy that will ask for a password when the file is opened or edited, and you can add a watermark with someone's name in it, but that's about it. What you're describing was probably created using some third-party software, probably some kind of DRM technology.
I find a solution with Acrobat Dc. I will put a DRM note in the slide master of Power Point. Hence, the note will appear on each page of the document. After this, I convert the file in PDF with full protection.