Non owned auto coverage would insure your business for claims arising out of employees' use of their own autos in your business. For example, if an employee running an errand for the business were involved in a serious accident, the business would probably be sued as well as the employee.
It is important to note that coverage does not extend to the employee - it covers only the business itself. It is sometimes possible to obtain coverage for employees for an additional premium.
Hired auto coverage would extend your business auto coverage to vehicles which you might rent or borrow (excluding those of employees, partners or their households).