Turbo is prompting me for 2019 info but I still need to file for 2018

[mesquitebean]

Online TurboTax is for 2019 returns only.

To prepare a 2018 return, you'd need to use the CD/download software.  And it cannot be efiled.  It has to be printed, signed, and mailed.

You can buy the 2018 software here:
https://turbotax.intuit.com/personal-taxes/past-years-products/

Did you already start a 2018 return online and need to download the *.tax2018 data file to finish in the software?    If you already paid for 2018, TurboTax should furnish you the software to finish your started return, if applicable.

[mesquitebean]

You may also need this information.

Minimum system requirements for Windows version:
https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...

Minimum system requirements for Mac version:

https://ttlc.intuit.com/community/system-requirements/help/minimum-system-requirements-for-turbotax-...