Anything brought back to the U.S. must be declared. Some items will require duties, which is a fee similar to a tax that varies according to the item. Travelers should keep all receipts of transactions abroad and hold these items in a separate bag for passing through customs. Certain products -- such as particular foods and medications -- are either prohibited or restricted from entering the U.S.
Certain immunizations are required before traveling abroad and this varies by country. Ideally one should set this up four to six months before the trip.
All United States citizens traveling internationally, including to Canada and Mexico, must have a passport issued by the State Department. Applications are at the local post office and maybe the library and your court's clerk office. Other requirements, depending on the country, may include a visa, a flight itinerary or onward travel.
