Your return's electronic filing status history records all e-filing activity related to the return, including the Electronic Postmark. You can print it out if needed.
TurboTax Online
https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp -- enter the Social Security number of the first taxpayer on the return and the ZIP code to retrieve your filing status history.
TurboTax CD/Download software
(Windows) From the TurboTax File menu, select Electronic Filing > Show Electronic Filing Status History.
(Mac) From the TurboTax File menu, select Check E-Filing Status.
