A more thorough explanation:

The Foraker Act is a federal law that was passed in 1900 to establish a civil government in Puerto Rico. However, it kept Puerto Rico outside of the U.S. customs area.

For example, if someone from Puerto Rico wanted to import goods into the United States, they would have to pay customs fees and follow U.S. customs regulations. This was not the case for Puerto Rico under the Foraker Act.

The Foraker Act was significant because it marked the first time that the United States had established a civil government in a territory that it had acquired through war. It also set a precedent for how the U.S. would govern its territories in the future.