Ok after some minutes of conversation on Telegram with OP, i confirm that OP is a scammer trying to motivate you to create an account of a shady fake exchange. He doesn't use BTC official network ''for security reason'' and wants only to do a internal transfer on his fake exchange.
I cannot say that I am surprised...
https://imgur.com/a/fNSi5Q0And I guess there goes the trick starts, after faking the deposit to you with that exchange. As you try to withdraw, there will be a message that you're required to deposit.
That's the usual trick that these scammers do.
Anyway, I'll quote the picture for others to see it.