What do customs duties apply to?

Customs duties specifically apply to taxes levied on goods that are imported from outside a country's borders, which includes imports from non-EU countries when considering the context of the European Union. This tax is imposed by governments as a means to control the amount and type of goods entering the country, protect domestic industries from foreign competition, and generate revenue.

When goods cross international borders, customs authorities assess these duties based on various factors, such as the value of the goods and the tariff classification. This process applies strictly to imported goods, ensuring that any products brought into the country from outside are subject to regulation and taxation. This duty is distinct from other forms of taxation and is specifically tailored to manage international trade. Therefore, the answer accurately captures the essence of what customs duties govern.