Every online casino has its own terms and conditions for its bonuses that are suited to the way its management team wants to run the business. That said, most follow a similar pattern that is tried and tested.
It is all but guaranteed that a reload bonus has wagering requirements attached to it. Many years ago, when online casinos were in their infancy, some people made vast sums of money, at the casinos’ expense, by signing up for bonuses, playing a few spins, and then withdrawing their balances.
Obviously, this giving away of money was great for the player but bad for business. This is why you are now required to wager a predetermined amount before you get complete control of the bonus money and, often, any winnings derived from it.