if a customer selects the cash-on-delivery payment option at checkout, the system automatically adds the "Cash On Delivery Fee" product to the cart. Conversely, if the customer chooses another payment option, this product is automatically removed from the cart. if a customer selects the "express" delivery option, the cash-on-delivery payment option

"Incorporate a pre-purchase insurance upsell product into the Shopify platform. This feature calculates a 10% fee based on the cart subtotal and applies it as the insurance fee. Essentially, customers are offered the option to protect their purchases with insurance before completing their transactions. The fee is dynamically calculated"