Yes, it can be manage from the backend Question email notification can be manage from Stores > Configuration > Magediary > Product Questions > Question Email Notification Answer email notification can be manage from Stores > Configuration > Magediary ...
The registered users can access all submitted inquiries from the My Account ⟶ My Product Inquiries section. Reference guide: https://magediary.com/docs/product-inquiry-support.html#my-account The guest users can access it by clicking on the View ...