How a Bill Becomes a Law. Creating laws is the U.S. House of Representatives ’ most important job. All laws in the United States begin as bills. Before a bill can become a law, it must be approved by the U.S. House of Representatives, the U.S. Senate, and the President.Let’s follow a bill’s journey to become law. If the U.S. House of Representatives and the U.S. Senate still believe the bill should become a law, they can hold another vote on the bill. 2  If two-thirds of the Representatives and Senators support the bill, the President’s veto is overridden and the bill becomes a law.