For most UCI researchers looking for a PDF version of a bill, ProQuest Congressional is the best starting point because the coverage is comprehensive and the search options are intuitive. Researchers looking for more recent bills (from 1993 or so) should also try one of the other options.
Bills, joint resolutions, concurrent resolutions, and simple resolutions are the four forms of Congressional legislation. Most common are bills. These can be permanent or temporary, general or special, or public or private. To become law, a federal bill needs the approval of both chambers of Congress and the President's signature (or re-passage by Congress over a presidential veto).
For more information, see:
A federal bill is designated by the letters "H.R." or "S." (based on its chamber of origin) and a number. Bills are assigned numbers sequentially during each session of Congress. Depending on the nature of the bill, Bluebook might require more citation information.
See Bluebook Rule 13.2. Examples include:
H.R. 4954, 109th Cong. (2006) (enacted).
S. 2459, 109th Cong. (2006).