In the Jupiter theme the Addon, Aliases, and Subdomains sections were consolidated into the Domains section. There is no way to break them back of of Domains as well.
Please refer to: Addon domains, Subdomains, and Aliases are missing from cPanel in Jupiter Theme
How to add-on subdomain at cPanel, can refer to : https://docs.cpanel.net/cpanel/domains/subdomains/
