The laws passed during each session of Congress are published in the United States Statutes at Large.
These federal session laws are called public laws.
The United States Statutes at Large, typically referred to as the Statutes at Large, is the permanent collection of all laws and resolutions enacted during each session of Congress. The Statutes at Large is prepared and published by the Office of the Federal Register (OFR), National Archives and Records Administration (NARA).
Every public and private law passed by Congress is published in the Statutes at Large in order of the date it was enacted into law. The laws are arranged by Public Law number. For example Public Law 103-3, the Family and Medical Leave Act of 1993, was the 3rd law passed by the 103rd Congress. It can be cited as Public Law 103-3. Or in LexisNexis Academic searching it is cited as 103 P.L. 3
Public laws are also cited by volume and page number that they appear in the print Statutes at Large. For example Public Law 103-3 appears in volume 107 of the Statutes at Large on page 6. So it can also be cited as 107 Stat. 6
Then these individual session laws such as P.L. 103-3, get incorporated into a compilation of existing law called the United State Code. The United States Code will contain those parts of an orginal law that are still in effect - along with all of the subsequent amendments to that law - to create the existing law. A session law may be pigeon holed into several sections of the U.S. Code. The print Statutes at Large will have entries in the margin showing the sections of the U.S. Code that a session law ends up in the U.S. Code.
Also included in the United States Statutes at Large are concurrent resolutions, proclamations by the President, proposed and ratified amendments to the Constitution, and reorganization plans.
Congress.gov is also a good place to find Public Laws (session laws) passed since 1973.
Additional online resources: