To access your current or prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the bottom of the screen and on the section Your tax returns & documents click on Show. Click on the Year and Click on Download .tax file
You will need the 2017 TurboTax software to open the tax data file. The software can only be installed on personal computer, desktop or laptop, with either a Windows or Mac operating system.
Go to this TurboTax website to purchase and download the the prior year desktop editions - https://turbotax.intuit.com/personal-taxes/past-years-products/