Hi ! There is the same difference between "Vous" and "Tu" as between "Вы" and "Ты" in Russian. "Vous" is the polite and formal way to address someone whom you are not familiar with, or who is much older than you are, for instance. "Tu" is used with those whom you are familiar with : friends, members of your family, persons of the same age, colleagues etc. Both expressions "S'il vous plaît" and "S'il te plaît" mean the same "Please", but you've got to adjust your choice to the person you're speaking to. In case of doubt, it's better to use "Vous" than to sound too quickly familiar. Hope this will help.

as far as i know, the differences both of them are laid on situation whom we talk with? S.V.P or S'il vous plait is used in formal situation or someone who just we know, and S.T.P or S'il te plait is used in informal situation, parexemple talking with bestfriend or family, but the meaning is Thanks You