Zotero
Zotero is a fantastic bibliography and citation manager that is free, flexible, and intuitive. It allows customization and group collaboration.
Go to the registration page and sign up for a free account.
Next, download the following:
Standalone Zotero app for your computer
Zotero Connector for your internet browser.
Install the Zotero app on your computer and then make the following changes in the app's settings (to get to settings on a Mac, select Zotero → Preferences in the menu bar (or press and hold the ⌘, keys on your keyboard with the app open); to get to settings on a PC, select Edit → Preferences).
In the Sync tab under Settings, enter your username and password (this will ensure that you can access your Zotero library both from your computer and online).
In the Cite tab under Styles, ensure that the following three styles are installed (if they are not, click Get additional styles... and install them):
Chicago Manual of Style 17th edition (author-date)
Chicago Manual of Style 17th edition (full note)
Chicago Manual of Style 17th edition (note)
In the Cite tab under Word Processors, click Install Microsoft Word Add-in. Once the process finishes, restart Microsoft Word and ensure that you can now find a new Zotero tab in the Microsoft Word menu bar.
Optional: In the Advanced tab under Files and Folders, you can change the default directory where your data will be stored (recommended if you wanted to use something like Google Drive to automatically back up your data and PDFs).
Consult the Zotero Quick Start Guide to explore some of the useful features Zotero offers.