Add permission to shared document

Hey there,
I want add permissioon for editing the shared document. In broad sense, editing the shared document(white board) will remain off for all members while for owner it remains on. However, all can view the shared document(white board). So when a member wants write into the white board, he/she has to request the owner to allow him/her.

Is this a pre-built feature into Jitsi and we can turn it on somehow using any configs? Or do we need to alter the source code for this?

Nope there is no such feature.

Can we pass any custom headers to etherpad_base ?

You can do that in the nginx config that is doing the proxy to etherpad.