If you have an indepdently hosted WordPress blog, you can turn it into a Fediverse server using a special plug-in. This means that people on Mastodon etc. can follow your blog and interact with it.
You can install it on your blog by logging into the WordPress dashboard, go to Plugins > Add New, then search for "ActivityPub". The plug-in you want is called "ActivityPub" and is by Matias Pfefferle.
You can also see more info about it at https://wordpress.org/plugins/activitypub and the author is on the Fediverse at @pfefferle
Once it's installed, you can find the blog's Fediverse address in your WordPress dashboard's Users section, it's listed at the bottom of the user's profile options. You can copy and paste this address into the search box on Mastodon etc to interact with that user's blog.
You'll also see an ActivityPub section in the Settings menu.
Note : This plug-in only works on independently hosted WordPress-powered blogs. It doesn't work on Wordpress.com free blogs.