Every Wix API has a service object with predefined fields, which can’t be removed or changed. But sometimes, the fields that the object provides aren’t enough. For example, if your app uses the Order object for handling visitors' orders, you may want to include custom warranty information as part of the order. Out of the box, the Order object doesn't have a field for this.
Schema plugins solve this problem. You can use schema plugins to extend an object with additional fields. This allows you to store data that the object doesn’t otherwise support. Once added, these fields can be read and written using the object's regular endpoints, just like any other field in the object.
Currently, you can extend the following Wix eCommerce objects with schema plugins:
Learn more about schema plugins and how to implement them.