You just have to stick to legal, regulated online casino sites such as BetMGM, Caesars Palace Online Casino, FanDuel, Betway, bet365 and BetRivers. They offer great casino game ranges and they will pay out quickly and without any issues if you win.
As a rule, you have to present a valid identification document such as an identity card or passport and a so-called utility bill, i.e. a bill for telephone, gas or electricity. It is important that the address stored in your casino account appears on the invoice.