Account Level is the highest access meaning the person will have access to all the properties and views in the account.
Property Level can be thought of as websites, one site should have one property so if your business has multiple sites (or apps) then these will be separate properties so you can give the person access to just one site and not everything in your account.
View Levels are the lowest amount of access and restrict the person from doing much at all, these are usually just for viewing purposes.