You must have purchased one of the TurboTax desktop editions. The purchase of the desktop software does give you access to the online tax returns for prior tax years.
The requirement is to upgrade to the TurboTax online edition of Plus and then pay for the upgrade so that you can access prior year online tax returns.
You can also get free transcripts of your federal return from the IRS - http://www.irs.gov/Individuals/Get-Transcript
For a fee of $50 you can get a complete federal tax return from the IRS by completing Form 4506 - http://www.irs.gov/pub/irs-pdf/f4506.pdf
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 not be able to upgrade to the Plus edition for tax year 2018 since the TurboTax online editions for 2018 have closed to make way for the 2019 online editions. Once the 2019 online editions become available in December, at that time you can start a 2019 return and upgrade to Plus.
Or contact TurboTax support during business hours and see if there are any other options available for accessing a prior year online tax return.
Support is open from 5am to 5pm Pacific time, Monday thru Friday
Use this website to contact TurboTax support during business hours - https://support.turbotax.intuit.com/contact/
Support can also be reached by messaging them on these pages https://www.facebook.com/turbotax/ and https://twitter.com/TeamTurboTax
