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)
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.
Or go to this IRS website for free federal tax return transcripts - https://www.irs.gov/individuals/get-transcript
If you did not file a 2018 tax return -
To complete and file a 2018 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2018 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2018 tax return can only be printed and mailed, it cannot be e-filed.
If you did a 2018 tax return and it has been processed by the IRS, you should be able to find a transcript of the return on this IRS web site: https://www.irs.gov/individuals/get-transcript
If you think you used the TurboTax online product to do it, you can look on your TurboTax accounts. You may have more than one. Here is a link to find accounts: https://ttlc.intuit.com/community/account-management/help/how-many-turbotax-accounts-do-i-have/00/26...