I'm assuming you mean anyone and anybody. There is really no difference between them. Both mean any person. Anyone is slightly more formal but it is subtle. The adjective phrases, "Any one..." or "Any body...." are different. "Any one ..." , is meant to single out specific items from a group. " Any one of these cells could contain a virus." "Any body ..", is meant to single out a dead, human bodies from a group. " Any body that has the rash must be sent to the CDC ." One exception would be, "Any body of water ...". "Anybody/anyone that has the rash must be sent to the CDC ", refers to living individuals "Any body that has the rash must be sent to the CDC ", refers to deceased individuals. There are more subtleties and exceptions but this covers the majority of cases. Hope that helps.

There is no difference between the two words. You do have to put the two words together, it would be "anybody" and "anyone" You can say... Is anybody there? Is anyone there? It means the same thing, but i think in writing it sounds better with anyone.

No difference