Wordpress is a content management system that allows you to create your own website by buying and hosting a domain, then customizing your own site. It's one of the most popular site-building websites, alongside Wix, Godaddy, and many other platforms. Most people use Wordpress to create blogs and generate passive income. This means they'll write articles and post them on their website, regularly updating the site several times per week, and sometimes even multiple times a day. As time goes on, the blog will gain "traffic", or viewers who frequent the site. The blogger will generally sign up for an affiliate program like Google Adsense, which puts ads on their website and gives them money each tmie someone clicks on the ad. So, the larger the audience, the more revenue.
Of course, there are others that create e-stores, or just set up niche sites for others ti visit. Wordpress is a very flexible platform that allows you the creativity and freedom to create whatever website you want.