Creating subdomains via SSH

Hi, Domains cost a fortune (all the work around) and each time that I have a new project, I used to create a domain. I will from now on create subdomains. I am now launching WPaaS with Hosting, Elementor as plugin and OceanWP for Theme. I need to create a demo by design/audience, so it would be good to be able to script the creation of sub domains. I checked cPanel forum, but it's not very clear for me. Do you guys have an example of such command please? I do not mind creatinsubdomains, then set permissions (did that before to set .htaccess and wp-config.php) with a second script. Cheers, Jimmy