So the problem here is that Citizen Legislation (also known as a referendum) is an element of direct democracy which is present in some form in all 50 states in the United States... but it's not present at the Federal Level at all. In most states, the barriers to Citizen Legislation is a high one, though certain states are more accommodating than others (As a rule, the further west you go on the lower 48, the more open to direct democracy a state becomes). Typically you would have to show that a percentage of voting citizens (usually a percentage of the number of people who participated in the last election) want this law on the ballot (not support it mind you... there are people who don't care about the law one way or the other, but will support what the voting public says about it on referendum.). Then it has to pass a majority vote of a set threshold.
The U.S. Constitution is set to a very "representative democracy" approach and can be seen in how little the citizens have the ability to directly elect government officials (In modern day, you can directly elect your representative and both senators. Historically, Senators were indirectly elected by the State Legislatures but this was found to be more frustrating than popular elections because the State Legislatures were prone to bickering over who to elect, leaving vacant seats in the Senate with no ability to fill them.). The President and Vice President have always been indirectly elected (by the Electoral College), the cabinet is always appointed by the president, and the Supreme Court is also Presidential Appointment.
Even jobs that's state or local level equivelent are not direct elections in the United States. For example, U.S. Marshal's local level equivelent are Sheriffs, which with rare exception are elected officials. But the Marshal's are appointed by the President.
Suffice to say, the only way to get federal legislation passed is... by calling your Reps and Senators. To get an amendment to the constitution to legalize it, you need 2/3rds of both houses of congress and 3/4ths of all states to pass the amendment. Good luck with that.