Sales Receipt, Invoice, ???

To complete an order for our business in QBO, we pull up customer, fill in product ordered. But, we need to add shipping charges before it is charged to their Credit Card. During this busy seaon, there is not time for customer to wait on phone while we look up the shipping charge in USPS but we can’t save the Sales Receipt with out it charging the customer. Is there a way to save it? Thank you for your help.