TurboTax generates From 8606 Part III automatically. Under Wages & Income (or Personal Income) -> Retirement Plans and Social Security -> IRA, 401(k), Pension Plan Withdrawals (1099-R), enter the Form 1099-R that reports this distribution, answer the immediate follow-up questions to indicate that you "did something else with the money" (in other words, you did not roll it over to another Roth IRA), then click the continue button on the Your 1099-R Entries page and answer the additional question about your Roth IRA basis in regular contributions and conversions made before 2019.
If you made any Roth IRA contribution for 2019, you'll need to enter that under Deductions & Credits.
To view the resulting Form 8606 in online TurboTax, you'll need to pay for TurboTax before you can download the pdf file of your tax return before filing.