If you export goods, you must be clear on where the products have ‘originated’ in order to manage duty and customs requirements effectively.
The origin of your goods is either where they have been wholly obtained or produced or where the last significant work essential to the manufacture was undertaken.
Every stage of the supply chain can have a significant effect on whether you can import the goods using preferences. If goods are manufactured entirely in one country, you would expect their origin to be that country. However, if components are made in one country then assembled in another non-EU country, in combination with other components, the country of origin may be where the goods are assembled. See the guide on rules of origin.
• EU rules of origin are set on a country-by-country or product-by-product basis. You are advised to check the list of rules applying to your product/country here.
• Once you’re sure about the origin of your goods, you can manage the process of importing them under preference.
Source: (https://ec.europa.eu/trade/ )