Where do I customize the new member email notifications?
I cannot see this email in emails tab in foro settings.
It need some improvements - where can I do this?
This is not wpForo email, this is WordPress built-in email for new user registration. The user registration process and emails are provided by WordPress. wpForo only shoes custom form for that, but it's not responsive for functions. You should ask this question to Wordpress support. Or search for a plugin which allows to edit WordPress emails.