A subdomain like blog.yourdomain.com or app.yourdomain.com is a first-class address: its own DNS record, its own SSL certificate, and its own choice of what to serve. Creating one here is a single form, and the automation handles the parts that other hosts turn into three separate tickets.
Add it
In the panel, open your site and go to Domains, then Add domain. Enter the full subdomain, for example blog.yourdomain.com, and choose it as a subdomain of your existing domain. It appears in the domains table alongside the main domain, tagged as a subdomain.
The one decision: the document root
Every domain in the table has a document root, the folder its visitors are served from. For a subdomain there are exactly two sensible configurations:
- Its own folder, for example
public_html/blog, when the subdomain is a separate thing: a different app, a landing page, a staging copy. This is the usual choice. - The same folder as the main domain, when the subdomain should show the same site. Rare, and mostly used with apps that route by hostname themselves.
Pick the folder when you create it, and put an index.php or index.html in that folder. A subdomain pointing at an empty folder returns an error, not a blank page, which is worth knowing before you assume the subdomain itself failed.
DNS and SSL happen on their own
If your domain runs on our nameservers, the subdomain’s DNS record is created for you, and a free SSL certificate issues automatically once the record resolves, exactly as it does for the main domain. The Security page lists the subdomain with its own certificate status and its own Force HTTPS toggle. Give the whole chain up to an hour on a fresh subdomain, and read the SSL guide if the padlock takes longer than that.
If your DNS is managed elsewhere, the record is your job: add the subdomain at your DNS provider pointing the same place your main domain points, and everything else proceeds the same way. The Cloudflare guide covers the proxied case.
What a subdomain is not
It is not a new hosting account, and it does not consume one of anything. Subdomains live inside the site that owns the parent domain, share its storage, and are managed from the same panel screens. If what you actually want is a genuinely separate site with separate access, that is an additional website rather than a subdomain, and worth a message to support to set up the right way.