Citing is to research as "assist" is to goal in soccer (or another sport): record is kept (statistics) and rewards follow: recognition and remuneration.
A citation generator is a tool to help you create citations (also called references) for papers or projects.
Typically, you enter the information you have about the information source (author; title; publication information; page numbers; journal name, etc.) into the software or online website. That service uses the rules of the citation style to create a citation that adheres to those rules.
College of San Mateo Library subscribes to NoodleTools and has informed instructors about that very useful tool. There are other tools online available and a few are listed below.