See the information below from a TurboTax FAQ. After you've e-filed your return, you should see a screen that notifies you that your transmission was successful.
https://ttlc.intuit.com/replies/3301375
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
