AutoSSL is the canonical solution for cPanel, which is enabled by default in cPanel for some time now.
It is by default configured to use the Comodo SSL provider (which is actually a cPanel sub-ordinate CA).
There is the option to use the Let’s Encrypt SSL provider, which is installed separately, but still adheres to the AutoSSL framework.
AutoSSL uses the HTTP DCV challenge over IPv4 only. AutoSSL providers can nominate their own DCV paths (e.g.
/.well-known/pki-validation for the Comodo provider,
acme-challenge for the Let’s Encrypt one).
AutoSSL drives these providers asynchronously in the background and issues certificates opportunistically for all domains it can reasonable detect to succeed. It generally cannot be controlled by anybody except the administrator of the WHM/cPanel server.
cPanel also includes functionality that enables users to buy certificate directly from within their cPanel user interface from commercial providers that wish to integrate with cPanel.
Finally, there are non-AutoSSL WHM/cPanel plugins (third party ones) that exist for a variety of reasons, such as they existed before AutoSSL existed.
It’s not clear to me whether there is a straightforward way to detect this, apart from visiting the SSL/TLS interface in cPanel and seeing whether any certificates are already installed.
If your account hasn’t automatically received an AutoSSL certificate within a day or two of the account being created/domain being added, then almost certainly AutoSSL is disabled.
If you want, I can give you an account on the development server we use for our third-party plugin to see what all the interfaces look like.
Server admin can choose, Comodo/cPanel sub-ordinate CA is enabled by default on new cPanel installations.