To verify your account, you can do this, and it proves you own an official website connected to you.
"Link verification
Mastodon can cross-reference the links you put on your profile to prove that you are the real owner of those links.
The official site you add your profile needs to include a link back to the your new Mastodon profile with the rel="me" attribute in the code of the link tag."
Once both are in place it gives ou a free verified mark proving you are you!