Referral codes are meant to bring in new people, someone can use your referral code to create their account, and if they deposit $200, you will both receive $10* in BTC. *$10 in BTC is distributed when a new user makes the first deposit of $200 or more using your referral code at the time of sign-up. You can find your referral code by tapping on the "Profile" button and then on the "Refer your friends" section.