Zotero is free and open-source reference management software to manage bibliographic data and related research materials (such as PDF files). Notable features include web browser integration, online syncing, generation of in-text citations, footnotes and bibliographies, as well as integration with the word processors.
This video covers the basics of Zotero so you can get started integrating into your research and writing workflow. Check out https://www.zotero.org for guides and support.