If you used the Online version for 2017, your information will automatically transfer over when you start your return as long as you are in the same account as you used in 2017. All you need to do is sign in with the same login you used last year, and TurboTax will transfer your information over.
Can't remember last year's login? Try our account recovery tool. See the following for more information on transferring prior year information into your 2018 return for Online.
How do I transfer last year's return into TurboTax Online?