Function fees use Shopify Functions to bundle the fees as part of a product or to bundle them with other fees at the checkout. They are fast and reliable, and support percentage-based fees for all merchants. They work well for most fees like credit card processing fees, recycling fees, bottle deposits, and surcharges. The Function method is recommended for most stores.
Block fees show fees as separate line items in the checkout. Some stores prefer this for aesthetic reasons or to meet specific workflow needs. They are commonly used by Shopify Plus merchants on our Growth plan, especially when they want discounts to apply to percentage-based subtotal fees.