Question
You may ask yourself if you can create reseller accounts or cPanel accounts with adduser within the command line.
Answer
No, because adduser is not the same as creating the same via the API/WHM. It is not recommended that you create an account using adduser.
If you wish to create an account via the command line, please refer to the following API: https://api.docs.cpanel.net/openapi/whm/operation/createacct/.
You can also create a reseller account with the API mentioned above utilizing the reseller parameter.