Creating custom fields in Check-in

[Hamartia123]

We utilize Snipe-it for managing assets in the IT dept of our local Hospital. I was asked to figure out if it is possible to add custom fields to the check-in. What they want is a field that can link to the asset the one being checked in is to be replaced by(can just be a text box), along with a listbox field that would be used to specify information about data destruction. We are on V5.2.0 build 6339. Any help would be hugely appreciated!