This is a feature of the mail server, not phplist. you would need to ask registrar-servers.com of there is a way to modify the settings on the mail server.
Can you please tell where in the Code shall I add the Reply-To header to reflect in Email.
My host doesn’t over write the Reply-To header. So If I can add my To Address in Reply-To header then my problem would be 80% Solved. The headers will show something like below.
from: Shams smtp@boxygen.ml
reply-to: Shams mail@boxygen.ml
to: Faisal Ayub faisal.ayub@boxygen.pk
date: Sat, Nov 26, 2016 at 3:37 PM
subject: Here is the subject
signed-by: boxygen.ml
encryption: Standard (TLS) Learn more