Dipping your toe into the ocean of international trade can be eased by exporting to or importing from a country with which the United States is a Free Trade Agreement (FTA) partner. A Free Trade Agreement generally allows for low- or duty-free import from a partner country and has many other benefits, as well. Many U.S. companies can easily begin selling to Canada or Mexico barrier-free due to the former North American Free Trade Agreement (NAFTA) which has been replaced by the United States Mexico Canada Agreement (USMCA) as of July 1, 2020.
The United States has Free Trade Agreements with other countries outside of Canada and Mexico, as well. There are agreements with countries such as Australia, Colombia, Morocco and Singapore, among others. See the current full list of U.S. FTA partner countries at the following page.