Asset type in the system is equivalent to Department, Unit or Sector your people belongs to.
You can set up this by following the guide provided in here.
Renaming is also possible. Just go to Settings->Types under People Set Up->press edit button for the asset type you want to be renamed->edit->Save.
Archiving, on the other hand is also possible, but not recommended especially if there are already people attached to that asset type. Should you wish to do so, you may speak to one of our team members or contact firstname.lastname@example.org.