Bills come from members of Congress or their constituents, which is the general people living in the area that a member represents. The ideas for bills can be presented from the state legislature, the governor and individuals within the representatives office.
Ideas for bills can also come from the president or offices of the executive branch. If the members of Congress think the idea is sound and would serve the people well, then they will sponsor it and have it submitted to a committee to be studied. The members of Congress can also present their own ideas to the committees for bill consideration. If the committee approves the idea it becomes a bill and is sent to the floor at the House of Representatives to begin the approval process.