Hi @sacredabhishek and thank you so much for the additional information.
As it stands, this is not possible in Asana at the moment but I agree that the capability of sending and receiving email to and from the outside would be very useful.
We have a thread regarding this topic on the #productfeedback category. If you haven’t yet, feel free to add your vote and comment to the main thread: Mailbox integrated to Asana to communicate with external users.
I hope you have a nice day!