You download your .tax2017 datafile from your Online account....and finish it using the desktop software.
https://ttlc.intuit.com/questions/2559403-how-do-i-finish-a-prior-year-return-that-i-started-in-turb...
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You will be required to print it out Mail it in to the IRS, and separately to your state.
(No e-filing of anything except a 2018 tax return is allowed at this late date.)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
