If you have an independently hosted WordPress blog, you can turn it into a Fediverse server by installing the WordPress ActivityPub plugin. This means people can follow your blog from Mastodon etc.
Here's how to do it:
1. Go to your WordPress dashboard's Plugins section, click "add new" and search for "ActivityPub" . Click "install now" on the plugin, and when it has finished installing, click "activate".
2. On the WordPress dashboard, go to the "Users" section. Click on your username and scroll to the bottom to find your Fediverse address. Share this address with whoever wants to follow your blog on Mastodon etc.
3. To alter the plugin's settings, on your WordPress dashboard go to Settings > ActivityPub
If you want to switch off or remove the plugin, go to "plugins", then "deactivate" or "delete".
NOTE: This plugin only works with independently hosted WordPress sites. It doesn't work with free accounts on WordPress.com.
p.s. If you use the WordPress ActivityPub plugin, it's a really good idea to donate to @pfefferle as they are the one who put the hard work in to create and maintain it.
You can find donation links on Matthias's donation page at:
(Thank you for pointing this out @mikka!)