Shopp allows merchants to collect product-specific customization information from customers using custom product inputs. This is useful for capturing information from customers for a product such as custom engraving messages, gift notes for a product, or specific handling instructions.
Custom inputs are currently a developer implemented feature added to the store’s templates. This is an intentional design choice to prevent breaking the site by removing inputs for which a developer has tied specific data processing. Instead, custom inputs must be added to the shopping template pages using specialized Shopp code to generate the fields. While this limits the ease and accessibility of setting up new custom inputs, it protects the shopping experience for customers ensuring that custom functionality created by your developer, works as intended and as the customer expects.
For more information about setting up custom input fields for your products, ask your developer, or consult the Theme API documentation.