You cannot prepare a 2019 return in Online TurboTax, which is only for 2020 returns. To prepare a 2019 return with TurboTax you would need to purchase 2019 desktop software (CD/download) and install it on your computer.
You can purchase 2019 software as a download from TurboTax here:
https://turbotax.intuit.com/personal-taxes/past-years-products/
Or you may still be able to find it discounted as a CD or download at an authorized reputable retailer like Amazon. If purchased outside of TurboTax, be aware that the Deluxe Edition comes in 2 versions--one that is a combo Federal and State version, and one that is Federal-only. Basic Edition does not include a state return and cannot import from ItsDeductible. CAUTION: There are Internet scam sites selling pirated software or trying to get your personal info, plant malware, etc. Only purchase from an authorized retailer, which are large companies like Amazon, Staples, Office Depot, Sams, Costco, NewEgg, etc. Some of these may no longer be selling 2019 product.
The 2019 return cannot be efiled. It has to be printed, signed, dated, and mailed. It's recommended to mail by a method that has tracking such as certified mail, priority mail, etc. Mail the Federal return to the IRS, and mail the state return (if applicable) to the state tax agency.