Many companies asked me if I know WordPress and I don’t know where to learn it.
WP has its own training materials - and there are others you can find on the web.
What FCC teaches here probably won’t help much unless you are getting into writing your own templates, etc.
FYI there’s wordpress.com and wordpress.org. The .com domain is the commercial hosted version of WordPress . At wordpress.org you can learn about the self-hosted version. To learn how to install wordpress and how to use it (how to blog, how to customize it as an end-user, as admin or author etc.), go to https://wordpress.org/support/. There is also the “Theme Handbook” from which you can learn how to build themes.