Zotero is a tool called a citation manager, or reference manager. It is designed to store, manage, and cite bibliographic references such as books, articles, webpages, videos, and more.
Use Zotero to collect and organize information and sources; download and save full-text PDFs; and generate bibliographies, full citations, and even in-text citations while you write!
This very brief video explains what Zotero is and shows you how it works: