http://certbot.iykpqm7jiradoeezzkhj7c4b33g4hbgfwelht2evxxeicbpjy44c7ead.onion
That means, for example, that if you use a web browser to go to your domain using http://, your web server answers and some kind of content comes up (even if it’s just a default welcome page rather than the final version of your site). Some methods of using Certbot have this as a prerequisite, so you’ll have a smoother experience if you already have a site set up with HTTP.