If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created. TurboTax does not store online any returns completed using the desktop editions.
You will have to get the 2018 tax data file from the old computer and copy that file to the new computer so that the 2018 tax data can transfer to a new 2019 tax return. The tax data file has a file extension of .tax2018. By default the tax data file and any saved PDF's of your tax return are stored in the Documents directory and in the TurboTax folder on a Windows based PC.
