You cannot use this year's TurboTax Online to file your 2018 tax return. TurboTax Online can only be used to file the current year's tax return (20190. And you cannot transfer your work to a 2018 tax return. You would have to start afresh.
Please follow the instructions in this TurboTax Help topic to prepare your 2018 tax return.
If you have not filed from Turbo Tax yet and entered 2018 info into the 2019 Online version you can try to clear and start over. Then use Turbo Tax for 2019.
Online is only good for 2019 now. If you tried to use the Online version for 2018 and entered 2018 info into the 2019 Online version you can try to clear and start over
Or you can leave this account and set up a new account to do 2019. How to start another return in the Online version
Then do you still need to file 2018? To do 2018 you have to buy the Desktop Download program here
Or If you have a simple return You can fill out the blank forms for free.
Here is the IRS 2018 Form 1040
And instructions https://www.irs.gov/pub/irs-prior/i1040gi--2018.pdf
2018 Tax and EIC Tables https://www.irs.gov/pub/irs-prior/i1040tt--2018.pdf
IRS 2018 Schedules 1 thru 6 (only if needed)
Don’t forget your state. And you will have to print and mail your returns. So be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.