A wagering requirement (also known as playthrough or rollover) is a multiplier that determines how many times you must bet the bonus funds before they turn into withdrawable cash. This mechanism exists to prevent players from claiming a bonus and immediately withdrawing it, which ensures the platform can sustain these offers.
It is vital to distinguish between Bonus Wagering (only the bonus amount is multiplied) and Deposit + Bonus Wagering (both your deposit and the bonus are multiplied). The latter significantly increases the amount of betting required to clear the bonus.
For example, if you have a wagering requirement, you must track your total bets until the requirement is met. You can find the specific multiplier for any given offer listed clearly in the "Promotions" section of your account. Once the target is hit, the remaining bonus funds are moved to your real money balance.