You can enter and change the information about your bank account (country, account holder, IBAN, BIC) anytime in the bank detail section of your account overview. To be able to receive winnings paid into your account it is essentail that this information is complete and correct.
IBAN and BIC code
Without IBAN and BIC code additional charges will be incurred for a money transfer between two EU countries. The IBAN consists of the country code, a check digit, the sort code and your account number. The BIC code specifies your banking institute in detail. IBAN as well as BIC can be obtained at your bank but are potentially also visible on bank statements or your account card.