ISF stands for Importer Security Filing.  ISF also is known as the 10+2 rule. When import goods to the USA, the importer must declare the details on the goods to the USA border control body. The shipping line should have done the AMS filling for the importer to submit the ISF. The latest 24 Hours of cargo loading from the origin county consignee should submit the ISF and failing to do such leads to huge penalties.