In cPanel, there is an icon labeled “Subdomains.” Click that. It takes you to the subdomain management page. Here you can setup subdomains and associate them with specific folders in your file system.
If you are trying to setup wildcard subdomains (for example, for WordPress Multisite), use an asterisk ( * ) as the subdomain, and associate the subdomain with the same folder as your main WordPress install.
This is a different tool than the DNS editor. You will need to do this even if you manage your domain at a different registrar — cPanel uses these settings to route requests once they have arrived at the server. (It also updates the DNS records as required, but only if the domain uses the nameservers associated with your cPanel account).
If your site is actually hosted somewhere else, and you just manage the domains from this cPanel account, then ignore the instructions above and just use the DNS Zone Editor.
