Hi @Martha1138
Airbnb does not allow you to charge a security deposit unless you are using an API connected software channel manager. You would have to rely on Aircover to process any damage to your property (hopefully you have also obtained your own insurance specific to short term rentals).
Security Deposits
https://www.airbnb.com/help/article/140
"Hosts aren’t allowed to charge guests a security deposit through our Resolution Center or outside the Airbnb platform. Instead, we inform guests at the time of booking that their payment method may be charged if they cause damage during a stay.
There is one exception: Hosts who manage their listings with API-connected software can set a security deposit using our offline fees feature. If a Host has done this, the deposit requirements will be clearly communicated during the booking process."