Shopify provides a way for merchants to capture information entered by customers using line item properties and cart attributes. These data are stored as part of the order data in the Shopify store.

Line item properties are mainly used to provide line item/product-level customization for the customer. For example, if you're selling jewelry, you may provide an option to enter a custom engraving for each item purchased. There are apps out there such as ShopPad's Infinite Options and BOLD's …