From the Summary of Introduction to the Legislative Process in the U.S. Congress (R42843, Nov. 15, 2018):
This report introduces the main steps through which a bill (or other item of business) may travel in the legislative process -— from introduction to committee and floor consideration to possible presidential consideration. However, the process by which a bill can become law is rarely predictable and can vary significantly from bill to bill. In fact, for many bills, the process will not follow the sequence of congressional stages that are often understood to make up the legislative process. This report presents a look at each of the common stages through which a bill may move, but complications and variations abound in practice.