A bill of lading listing the items to be imported.

An official invoice that lists the country of origin, purchase price, and HTS tariff codes of the goods imported.

A packing list that details the imported goods.

An arrival notice provided by the freight agent.

Importer having annual Bond and signed POA(Power Of Attorney to customs broker).

Other documents when government authorities requires, like CBP, USDA, FDA, CBSA.