Public laws are laws which affect the country as a whole.
This contrasts with private laws, which affect a particular segment of the population, such as an individual, family, or small group.
The vast majority of laws passed by Congress are public laws.
We cite public laws with the abbreviation Pub. L. No., which indicates that the law is a public law, followed by the number of the Congress which passed the law and the number of the law.
For example, Pub. L. No. 112-1 is the citation for the 1st public law passed by the 112th Congress.
You can view a chronological list of public laws passed by Congress here.