Do you have to provide certificate of origin to customers wh

Export to South Korea is basically to apply for China South Korea FTA certificate of origin to provide it to foreign customers for customs clearance. Even if the customer does not ask for it, we should provide it to the customer, because if the customer does not require it, it may be that the customer does not know. When the customer provides the FTA certificate of origin to the customs during customs clearance, the tariff can be reduced, which can reduce the import cost of customers and promote the secondary cooperation, But we can't spend a few money to get the certificate of origin. Why not provide it to customers.