The wagering requirement (also called playthrough or rollover) is a multiplier that dictates how many times you must bet your bonus funds before they can be withdrawn as cash. This exists to prevent players from claiming a bonus and immediately withdrawing it, which allows the platform to offer these incentives in the first place.
There are two main types of wagering: Bonus-Only, where only the credited bonus amount is subject to the multiplier, and Bonus + Deposit, where both the bonus and the initial deposit must be wagered. The latter effectively increases the total amount you need to bet before cashing out.
Progress is tracked automatically in your account. For example, if you have a bonus and a specific multiplier, every bet you place reduces the remaining wagering total. The exact multiplier for any specific offer is clearly displayed alongside the promotion in your account dashboard.