If you are carrying your items with you when you arrive in the US, you need to complete the Customs and Border Protection (CBP) Form 6059B "Customs Declaration."
If you are shipping your goods separately, you must complete CBP Form 3299 "Declaration For Free Entry of Unaccompanied Articles."
When you move your goods with a professional international moving company, your move specialist will help you prepare the required forms. You must provide a complete inventory of the goods you are bringing. The descriptors “Household goods” or “household effects” are not sufficient.