How to add BCC ?

Hi!

Yes, you can add extra email headers using this filter: https://advancedforms.github.io/filters/af-form-email-headers/

Why it’s not possible to configure this parameter directly in the administration ?

It could be but I’ve opted to keep the admin panel simpler and move some functionality to hooks instead.

If there is enough interest in a feature I normally add it to the admin as well but there hasn’t been much for BCC specifically!