English papers – Registration ?

Hello guys, I’m pretty fresh in the motorcycle business and I would like to buy a machine now. At mobile I found a Kawasaki ZX6R built in 2000. But the machine comes from England and has an English registration. According to the owner are so-called V5 papers (since my question is what are V5 papers?). So I’m also interested in what you need to register the machine here. I hope you can help me… Greetings Fabian