Why are you expecting it by mail? Did you select that? Has your return been accepted by the IRS? Did you efile? Did you go all the way through the File tab, through the 3 steps and hit the big orange Transmit Returns Now button?
When you efile you get back 2 emails. The first email only confirms the transmission. The second email says if the IRS (or state) Accepted or Rejected your efile. And check your spam folder for them.
When you log into your account you should also see the status and if it was Accepted or Rejected, Started, Printed, Ready to Mail, etc. What does it say?