What version are you using for this year 2018? You need a paid version.
To access your current or prior year tax returns sign onto the TurboTax website with the userID 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/print return (PDF)
Why you have to pay to access prior years
https://ttlc.intuit.com/community/charges-and-fees/help/why-do-i-have-to-pay-to-access-my-prior-year-return/00/27153