The federal income tax return is a Form 1040.
To access your current or prior year online 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)
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
You mean your Form 1040? Right now you cannot purchase PLUS in order to access your past year returns. The system is in transition from 2018 to 2019. Until that is complete sometime in December, it is not possible to purchase PLUS (for $19.99) to gain access to your past returns.
Meanwhile you could get a free transcript from the IRS or pay the IRS $50 for an exact copy.
You can get a free transcript from the IRS:
When you file your 2019 tax return, remember this hassle and avoid it:
Every year, before mid-October, print a copy of your current year tax return and save it as a tax file and pdf, too. That way you will have it when you need it for school, a loan, next year’s tax return, etc. without going through a lot of aggravation (and expense) to get it.