You didn't say whether you used TurboTax Online or the CD/Download TurboTax software for your 2019 tax return. If you used TurboTax Online, your tax return is stored on TurboTax's computers. You can use any computer to amend it. Go to the link below and follow the instructions for TurboTax Online.
If you used the CD/Download TurboTax software, you will have to either use the same computer that you used for the original tax return, or install the 2019 TurboTax software on the computer you are using now. You will need the .tax2019 data file for the tax return. If the .tax2019 file includes a state tax return, you have to install the state software before you can open the file.
If you don't have the .tax2019 file, you will have to recreate the original tax return, making sure that it exactly matches the return that you filed. Then you can amend it.
In any case, see the FAQ at the following link for instructions to amend your 2019 tax return.
How do I amend my 2019 return?
