The prior year tax data files and any saved PDF's of your tax returns remain on your computer where they were created. Those are Not transferred to the online program if you decide to complete and file a 2019 tax return using the TurboTax online editions.
You can transfer the prior year tax data from your computer to the 2019 online return but the actual prior year tax data file remains on your computer.
See this TurboTax support FAQ for transferring prior year tax data to the online editions - https://ttlc.intuit.com/community/entering-importing/help/how-do-i-transfer-last-year-s-return-into-...
