Once a block is found and your reward is calculated from your scoring hash rate, it appears as an unconfirmed reward on your account dashboard. At that point, you have to wait for a certain number of blocks (depending on the cryptocurrency) until your reward becomes confirmed = spendable. After these confirmations, it is relatively certain that the block is permanent so the transactions in it are final (i.e. immutable) and your earned coins are available for payout. However, you must reach your payout threshold before any payout can be made.