So I filed my taxes online but I have to mail my returns. If I do not mail them will it be as if I never filed?

If you e-filed your 2019 tax return and it was accepted then you have no need to mail anything to the IRS.

You complete your tax return by finishing all 3 Steps in the File section. In Step 3, to e-file your tax return, you must click on the large Orange button labeled "Transmit my returns now".

After completing the File section and e-filing your tax return you will receive two emails from TurboTax. The first email when your tax return was transmitted and the second email when the tax return has either been accepted or rejected.

Yes---it will be just like you did nothing.   Unless you successfully e-file OR print, sign and mail your return, it will be same as if you wrote a check for your car payment and put the envelope in your sock drawer.