The process by which bills are considered and laws enacted is referred to as the legislative process. All legislation begins as an idea or concept and becomes a bill when a member of Congress decides to introduce that idea and authors a bill.
During each session of the United States Congress thousands of bills are introduced and considered. However, because of the complex legislative process, only a small percentage of these bills will ever reach the President's desk for final approval.
This legislative process flowchart illustrates how bills move through Congress. For more detailed information about the legislative process and how bills become laws, vist the Thomas (Library of Congress) website.