A Bill becomes a law when it is introduced to either the House or the Senate first. Once it goes through the committee and conference to be discussed on. Then they vote and if the majority wins the bill passes. The same system is repeated on the other side of congress whether it is House or Senate. If majority passes the law then it will go to the judicial branch for a Judicial review to see if the bill is correct and ethical to our Bill of Rights and to see if its constitutional. It then goes to the president where he can veto it or pass it, he can also let it sit or just stow it away for a couple months. If he vetoes it then it can go back through congress and get a 2/3 vote and still pass