Both WordPress and Joomla are open source blogging platform and content management system.
As of now, WordPress has the largest user base of any self-hosted blogging tool in the world, about 20% usage at the time of this writing. This is about 60 million sites as of this writing today. Joomla is the next with about 3%. User can either use WordPress.com or WordPress.org for their blogging, with the latter option allowing more flexibility and customization with extensibility.
With WordPress, you can build a blog or website and engage as a community. WordPress is constantly evolving and is part of a larger ecosystem to create the best web experience for the users. The WordPress blog provides a means for your expression. It has become the platform of choice for new blogs and websites. You may learn about WordPress by visiting this site created by WordPress Learning Platform.
The online training program from Wealthy Affiliate will be using WordPress as the CMS (Content Management System) to help you create a powerful website for your online business. You can visit my Get Started page to begin your online training.
Many Wealthy Affiliate member also created various blog post for you to learn about WordPress. You can check out the link provided by Shawn Martin for the good stuff for WordPress users.
WordPress has been used by many Webmaster and you can find many kind of tutorials provided by experts like at WPBegineer. For those prefer to learn by video, you can watch WPBeginner on YouTube. If you want to speed up your research process for your content creation, you may refer to the Google Search Operators cheat sheet.
One of the top influencers on the web, Neil Patel recently wrote an article teaching you 17 Powerful WordPress Marketing Tips. You can have a read and pick up some tips from him.
Joomla was launched in 2005 and it was the successor of Mambo from Australia. Since then, Joomla has many upgrades and improvement with the latest version in 3.x series focusing on mobile-friendly version.