How can i Enable / Disable the confirmation email ?
For the Subscription Confirmation you should use "Enable Subscription Confirmation" option in Forums > Settings > Features Tab. Documentation: https://wpforo.com/docs/root/wpforo-settings/features/#double-opt-in
For the new user registration confirmation you should use "Enable User Registration email confirmation" option in the same admin page.Documentation: https://wpforo.com/docs/root/wpforo-settings/features/#registration-email-confirmation
P.S. Make sure you've checked this admin page if you don't find any setting next time.