If you filed with TurboTax Online, your returns are in your account. When you sign into your account, click on Previous Taxes on the left-hand menu, see attached.
If you did not file with TurboTax, you can obtain a transcript from the IRS or your state's Department of Revenue. Links are attached.
IRS - copies cost $50, but transcripts are free. - IRS copies and transcripts
For state information, click on your state from this list - State Department of Revenue List