In the UK, online gambling sites are required by law to comply with strict regulations to prevent money laundering and fraud. As part of these regulations, gambling operators have to verify the identities of their customers to ensure that they are of legal age to gamble and that their funds are obtained through legal means. Players will typically be asked for copies of their ID documents, such as a passport or driving licence. This is to confirm your identity and ensure that you are who you say you are.