The president is the head of the Executive Branch, which makes laws official. The president is elected by the country and serves a four-year term, the president is limited to two terms.
The Legislative branch is made up of two houses of Congress, The Senate and The House of Representatives. Senators can serve for 6 years and Representatives can serve 2 years. The Legislative Branch makes laws that are written, discussed, and voted on in Congress.
The Judicial Branch of the government is the Supreme Court and other federal courts. Their job is to explain the laws of this country under the Constitution. They also must decide if laws are unconstitutional. Supreme Court Justices serve for life.