This is a complicated question that perhaps can best be answered by viewing a flowchart of the process. See the link below for a good one. This chart refers to how bills become laws at the federal level. The state governments have their own processes, usually modeled after the federal process with various differences (i.e. states have their own laws about how to initiate the bill process).
Assuming your question applies to the federal level, however, bills can originate in the House or the Senate. They can be proposed by members of Congress, the Executive Branch, or many other ways. They go to committees, the committees hold hearings, the legislators listen to the views of lobbyists who try to convince them to vote in a certain way on the bills, there are endless debates, bills are often send back to committee, there are votes which require certain majorities depending on the nature of the bill. When all of the differences are worked out, in the U.S. system of checks and balances, the bill goes to the president and he can either sign it or veto it. If he vetoes it, it can still become a law because a majority vote in either the Senate or House can override a presidential veto. This does not happen very often.
There is also something called "the pocket veto". When Congress is adjourned, the president can reject a bill by simply refusing to sign it (it is as if he "put the bill in his pocket and forgot about it", hence the term ). Unlike a regular veto, Congress has neither the opportunity or constitutional authority to override a pocket veto.
Also, a bill can become a law without the president's signature. When Congress is not adjourned, and the president fails to either sign or veto a bill sent to him by the end of the 10-day period, it becomes law without his signature.
Enacting laws is a complicated process, and there are differing views as to whether it should be simplified or not. On the one hand, the process can get cumbersome, but on the other, we can overregulate ourselves if we make it too easy to pass bills. Many believe we have already overregulated ourselves in the United States, with way too many laws and too many lawyers and judges required to interpret the laws.
There have been a lot of efforts to refine the process, but most of these efforts have not been successful at the federal level. State laws is another issue, however.
In theory, the process of a bill becoming a law is pretty straightforward. The basic idea is that a bill must be passed by both houses of Congress. The houses must both pass identical forms of the bill. Once they have, it goes to the president to be signed. If the president signs it, the bill is law.
Of course, there are many details to the process that make it much less simple than this. First of all, bills have to be sent to committees to be considered and changed. Then the bills have to pass out of committee and be considered on the floor of each house. In this process, the bills tend to get changed and each house passes a different version. When this happens, the different versions must be considered by a conference committee. These people hammer out a compromise that allows both houses to pass the exact same bill.
Please follow the link below for more details.
A bill, in the field of law refers to a proposed law. The bill are put before the legislative arms of a government organizations such as legislature assembly, parliament, or congress for their consideration. These bill are put up by the individual members of such legislative bodies.
Bills put up before legislative bodies are discussed in their joint meetings, and then put to vote. During such discussions certain amendments may be proposed and incorporated in the bill. The exact procedure followed for discussion of bills and the nature of majority needed for passing the bill may be different for different legislative organizations. Also the nature of majority required may be different for different types of bills. For example while simple majority is enough for passing of most of the bills by Indian Parliament, two third majority is required for passing of constitutional amendments.
A bill once passed according to laid down procedures, than becomes a law or an act.