Understanding this process is an essential component of grassroots advocacy and civic engagement. While the process can be quite complex, when boiled down there are seven basic steps that lead to a bill becoming a law.

1. There needs to be an idea. The idea is written down by a member of Congress, either a senator or representative, and is submitted as a bill. 
2. The bill will be introduced to the legislative body in which it was written (either the Senate or House of Representatives). Then, the speaker of the house and the president pro tempore (or vice president/lieutenant governor) can assign the bill to a committee. 
3. Once in committee, the chairman of the committee decides which bills will receive public hearings and which ones will not. Members of the committee will research, discuss and offer amendments (or changes) to the bill. The public will also have a chance to testify on the bill and its proposed amendments. The chairman can then decide whether to offer the bill and/or amendments for vote by the whole committee. If passed out of committee, the bill and any amendments also passed go back to the entire chamber. 
4. The new bill (with any passed amendments) goes back to its originating chamber (either the Senate or House of Representatives). If called upon by the presiding officer, the entire chamber can then offer amendments to the bill and vote on the passage of the bill and/or any new amendments. 
5. If successfully passed out by the chamber, the bill then goes to the other chamber. For example, bills that originate in the Senate are passed to the House of Representatives, and vice versa for bills that originate in the House of Representatives. Once in the opposite chamber, the bills go through a very similar process of committee assignment. The new committee then decides which of the remaining bills will be heard, and then begins the same process of research, discussion, amendments, etc. If the bill is voted upon and passed out of committee, it (with any new amendments that were also voted upon), it goes back to the full chamber. The full chamber can again propose new amendments and vote on the bill. 
6. If both the Senate and House of Representatives have voted to pass the bill, then they must work out any difference between the two versions. For example, if the second chamber passed the bill with any new amendments, then the first chamber must also pass those new amendments. Both chambers must vote out the exact same bill. If it passes, it goes to the president (federal level) or governor (state level).
7. Finally, the president or governor then considers the bill. He or she can approve the bill and sign it into law, or veto the bill, stopping it from becoming a law.

It is important to note most bills never become a law. There are several ways to stop a bill, and the vast majority will stop before they can become a law. And, if a bill is lucky enough to get to the final stages and becomes a law, it often looks very different from the time it was introduced. Many times, amendments are added to change the bill and the law actually passed looks quite different from the bill that was introduced. 

As you can see, this process is quite complex, which is why it is so important to have people like you ready as grassroots advocates. Your voice is incredibly important and may need to be called upon at any of these stages.