I am uncertain if I filed my taxes last year. I filed a extension but don't know if I submitted them afterwards. How can I find out?

[NCOK]

I used turbo tax last year for doing my return and filing a extension. I can not remember if I actually filed them post extension. 

[JulieR]

You can also request a tax transcript using this link https://www.irs.gov/individuals/get-transcript to see if you filed last year.  If you started your return in TurboTax last year and filed the extension, but did not finish the return before the closing date, you'll need to start the return over again. The following provides instructions to complete and file your prior year return if it turns out you still need to do so. https://ttlc.intuit.com/replies/4186197