Most of the sportsbook might ask you to complete the KYC process when trying to withdraw your winnings.  Just look at their Terms of Service and you will find that they can ask for documentations whenever they want. During filling the KYC form, in order to match your information, most of them will ask for a government issued ID card and to verify you current place of residence, they will ask for utility bills. Last thing they might ask is to send them a selfie of yours while holding your ID card.