An order with custom option automatically generates a purchase order for production. First the product (without the custom option) will be picked from the warehouse and shipped for production. At the same time the supplier receives a purchase order with instructions as described in the order custom option.
After the supplier finished production, it will send back the product (together with the purchaseorder number) where a goods receive can start.
Finally the finished product with the custom option is ready to pick and pack.
A SKU with a custom option is seperated from inventory if the same SKU without custom option exists.
A Custom option is only visible for a supplier if the option is added to the supplier details