The billing address for any reservation is the address of the traveler for whom the reservation is created. If the traveller stays in the hotel for company purposes, the company can be added. In order to connect a traveler with a company, connect it in Reservation > General in the section Company. By doing so, the billing address in the folio is automatically changed to the corporate address, if you selected "Set company as debitor for the main folio".
Let's assume, a service was charged to the reservation, which should not be paid by the company, but individually by the traveller. + Add a new folio must be created with the private traveller billing address to move a charge from the first folio (with the company address) to the second.