Who Gets Copyrights when I send to a rapper?

[evanmays]

Hey guys, Evan Mays here! I have a quick question that's been bugging me. Let's say I make this banger beat. I then register the beat at the copyright office in the U.S.A. Then I send that beat to my rapping friend called Joe. I sell the beat exclusively to him for $100. My question is do I need to give him the copyrights for my advance and if so how do I give away a registered copyright?

Thanks in advance for the help!