When you create a product, enter "externalVendorSku" (seller product code) to use the code in your product order, etc. for management.
For other values, use the "extraProperties" (extra options) field.
This field is not exposed on the front end. It was made for the convenience of sellers. You can enter your own management code / other values that you need to save additionally.
For more details, refer to [Create Product API] for information on parameters.