The process is the same as with any other tax year except you will not be able to use TurboTax Online or file the return electronically. TurboTax Online is only used for current year tax returns (2020).
You can purchase and download a 2019 version of TurboTax to be installed on your computer in order to complete your 2019 return.
Here is a link to see the TurboTax 2019 products available: TurboTax 2019
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