CComment docs
Modifying the E-Mail templates
In CComment5 each E-Mail template is located in components/com_comment/views/mails. You can use the standard joomla template override technique to override the content of any of those templates. Here is what you need to do:
Create a mails folder in templates/your_joomla_template/html/com_comment/
Copy all the files (or only the files that you want to modify) from components/com_comment/views/mails/tmpl to your new mails folder & make the necessary modifications to them