As the old cPanel theme Paper Lantern is going to EOL, so cPanel has launched Jupiter theme. With most recent update of cPanel version, they have updated and minimized the Domains options. With Jupiter theme, they eliminate Addon Domains, Sub Domains options and merge them into Domains.
So if you are using Jupiter theme, then you can add new domain or sub domain from Domains option in cPanel:
When you will navigate to Domains, you need to click on blue button at top right with text “Create A New Domain”
By default, after adding domain name, system will point your domain to public_html directory. You need to point it to different separate Folder/Directory, so after entering domain name, uncheck the option “Share document root (/home/binbashi/public_html) with “myprimarydomain.com”
When you will uncheck it, the option for sub folder name will appear. You can keep it with domain name or can change to any of your desired name. It is recommended to keep it with domain name to avoid accidently removal.
Then click on Submit button and your Addon Domain will be ready.