A more thorough explanation:

The United States Marshals Service is a unit within the U.S. Department of Justice that is responsible for protecting federal courts and ensuring the effective operation of the judicial system. This means that U.S. marshals have the important job of making sure that the courts can do their work without any disruptions or threats to their safety.

One of the main tasks of U.S. marshals is to make arrests. This means that they are responsible for finding and apprehending people who have been accused of breaking federal laws. They also serve court papers, which means that they deliver legal documents to people who are involved in court cases. Finally, U.S. marshals enforce court orders, which means that they make sure that people follow the decisions that judges have made in court.

For example, if a person has been accused of a federal crime and a warrant has been issued for their arrest, U.S. marshals may be responsible for finding that person and bringing them into custody. They may also be responsible for delivering legal documents to witnesses who are needed to testify in court. Finally, if a judge has issued an order for a person to pay a fine or serve a sentence, U.S. marshals may be responsible for making sure that the person complies with that order.