Modifying heading text
I am trying to find where I can update the text that by default says "Customer details". I cannot find where to customize this text in the UI.
I found that the text is specified in the email-addresses.php file inside the template directory on the server. I can manually update the text in the PHP file, but the next time I update the plugin, that will be overwritten.
I can't find documentation for how to make my own file/version of a file for an existing Email Customizer template. I want to update the string mentioned above in such a way that it won't be overwritten when the plugin gets updated.