All people and products entering the US must be cleared for entry by Customs before exiting a bonded Customs area. In most cases, commercial products entering the US must be cleared through customs by a licensed US Customs Broker.
Depending on the types of products that you are importing and the mode there are many other regulations that must be followed. There can be severe penalties for failure to follow all proper regulations. It is critical for an importer to choose a service provider that is: experienced, has a comprehensive compliance plan, is C-TPAT Certified and possesses an excellent compliance record.