Zotero (pronounced "zoh-TAIR-oh") is a software application that collects, manages, and cites research sources. It's easy to use, connects with your web browser to download sources, and is free!
Zotero allows you to attach PDFs, add notes and images to your citations, organize collections for different projects, and create bibliographies in thousands of citation styles.
The four parts of Zotero are:
Functions: The main Zotero software application for storing, organizing, and annotating sources; then creating bibliographies in thousands of styles. Available for PC, Mac, and Linux.
Functions: Quick add items to your collection right from your browser. Available for Edge, Chrome, Firefox, and Safari.
Functions: add Zotero citations in Word, LibreOffice, and Google Docs
Functions: Backup access to collection, create groups, upgrade storage
Follow the below steps in sequence for the best results

Notes:
Zotero apps are now available for both Android and iOS via the relevant stores.

After you install the Zotero software and Connector(s), you need to set up your preferences to allow for syncing and cloud storage of your citations.