Was your tax return Accepted? Then it's too late to add it.
You can check your efile status here
https://turbotax.intuit.com/tax-tools/efile-status-lookup/
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.
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?
If your return Rejected then go back through the File tab to add or fix it.
