How do I enter multiple classes on the daily sales receipt?

I'm using QuickBooks Premier Retail Edition 2016. We have 2 forms of income. Sales from repairs/service and sales of inventory. I have created a repair class and an inventory class to be able to track our salaries, supplies, use items and the incomes from the two departments. When I go to the Retail - enter daily sales, the class is at the top and not on each line item. My daily sales receipts include both repairs and inventory sales. Is there a way to class the line items that I'm not seeing? Can I enter multiple receipts for the same day otherwise?