If your blog is in Blogger, do you know how to . . .

reply to commenter's questions? I tried to go onto Blogger Help and I couldn't pose my question in such a way that people understood what I was asking. You know when you make a comment on someone else's post, the program asks you for your email address and says it's not going to post the email address? I always assumed that the email address went to the original blogger so they could respond privately to the person and for security so that you know the person commenting is authentic. I cannot find where I can do that in Blogger, do ya'll know?