The primary duty of a restaurant cashier is to handle customer payments in the food service industry. Duties Of a Restaurant Cashier resolving customer complaints or issues putting takeout orders in containers or bags processing discounts and coupons greeting customers as they arrive answering customer questions assisting with or taking customer orders booking reservations upselling and making recommendations completing any return transactions maintaining cleanliness in register stations and tables closing or cashing out the register at the end of the day overseeing customer order completion assisting kitchen staff as needed processing payments and providing change and receipts