Both an authorization hold and a security deposit are funds that you hold in addition to the reservation payments. Security deposit is only available for Pro users at this time.
Use an authorization hold to make sure that the guest's credit card has enough funds to pay for their reservation. Use a security deposit to recoup funds when there are damages to the property during a guest's stay.
Both an authorization hold and a security deposit can be held for a maximum of 7 days, or 5 on a Visa credit card. Both can be charged or released manually during the hold time.
If you charge a deposit, it will show up on the guest's invoice, along with the reason for the charge (to help avoid chargebacks), and the total payout of the reservation will increase by the amount that was charged.