The pdf with your return would have a page of electronic filing instructions if you e-filed. If you mailed your return, only you would know when you took the envelope to a mailbox.
And if you have not deleted your emails from last year--check your emails.
When you e-file your federal return you will receive two emails from TurboTax. The first one will say that your return was submitted. The second email will tell you if your federal return was accepted or rejected. If you e-filed a state return, there will be a third email to tell you if the state accepted or rejected your state return.