The 5 digit PIN is not entered on a paper tax return.
Just print a copy of the Form 1040 then sign and date the form on page 2.
To access your current or prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on Download/print return (PDF)
Now if the actually want PROOF of filing for some unknown reason ... print a copy of the acceptance email TT sent you or the filing history ... Save a fresh PDF and look thru it for a sheet labeled "Electronic Postmark - Certification of Electronic Filing" .
That sheet tells you when you E-filed your "Federal" tax return electronically, and when it was accepted.......assuming you did file electronically and not by mail. Of course, filling out your tax forms is not the same as completing them, and then actually filing them. After e-filing them, you always should return to the software a few days later to make sure they were "Accepted" and not Rejected.