If at the beginning of doing your taxes with the online TurboTax and it didn't import your prior years information there are 2 reasons.
Using TurboTax online this year:
The first is you are not in the same account you filed with last year.
The second you used our desktop software last year and using the online version doesn't auto import.
https://ttlc.intuit.com/replies/3301662
If you are using the desktop version this year:
The tax year file from last year is either corrupted or missing.
The desktop version doesn't auto import from online
https://ttlc.intuit.com/replies/3302290