Upon the time that an enterprise's goods arrival at any one of EU countries customs or before leaving these customs, it needs to show its EORI number to the customs so as to make declaration. When exporting goods and materials from non-EU countries and making declaration to EU customs, an enterprise needs to show its EORI number. Even when enterprises or individuals need to import machinery and equipment, exhibition supplies, samples, office supplies and other goods from countries outside EU they also need to provide the EORI number, even if the enterprises or individuals usually do not engage in import and export business. When information exchange of goods flowing happens between all EU countries customs, an EORI number is also needed.