It depends. In the case of 2019, once the program has been paid for, TurboTax will prompt you to download the return to save it for your records. Next year, the prior year is loaded in so that you do not have to re-enter your name, address, etc.
If the download is for a prior year and you had not saved a PDF, you may have to pay for the return. Alternatively, for a fee, go to IRS Get Transcripts and request a Record of Account (Item 6.c.) on Form 4506-T for any "open year." This means any of the three past years, not counting the current tax filing year, can be requested: 2016, 2017, or 2018.
Other options would be to call 1-800-908-9946 or go to this IRS transcript resource page.
