If you attempt to withdraw money before fulfilling the wagering requirements, the casino won't allow it. Wagering requirements, also known as "playthrough" requirements, are conditions set by online casinos on their bonuses and promotions to avoid potential misuse.
You can't withdraw bonus bets or bet credits, but you can withdraw winnings. Bet credits and bonus bets cannot be withdrawn, but they can be used to wager on other sporting markets your sportsbook has to offer. Some sportsbooks make you use your bonus funds or bet credits in one lump sum.