In the PDF of your TurboTax return, the last page of the federal return should be an "electronic postmark" that shows your name, Social Security number, the date and time that you e-filed the return, and the date that the IRS accepted it.
You can check the status of an efiled Online return here
https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp
There will be a date and time stamp for when it was received and accepted. I think there is also a Show Efile History in the bottom left corner.
You can also order a Transcript from the IRS
https://www.irs.gov/Individuals/Get-Transcript
