Guided by other reviews on this website, I thought I'd give Citationsy a try. It seems pretty user-friendly, but...

Citationsy is fabulous for a host of reasons, especially because it is free. Citationsy is online and connected to your account, so you can access it from any computer once you log in, unlike some other citation managers that are tied to your desktop. You can create folders for each project, where citations can be kept in one place for each different project you have going. It does a great job of pulling information from the web or from publications given the title of the reference you are using. Perhaps most importantly, even though it is free it does not bombard you with ads the way some other free citation managers do, which essentially renders them useless. Citationsy has become my go-to citation manager (often more than the traditional ones!). References can easily be copied all at once for pasting into the document where they are needed as a bibliography.

If you have access to the doi, it's easy to copy and paste that into the search and your journal article will come up in the style you've chosen. This was really helpful as an extra way to go over my work late at night before a deadline. There are a wealth of styles available and ways to cite images, podcasts, etc. I love this tool.