There are two versions of TurboTax: TurboTax Online, and TurboTax Desktop. It sounds like you have used the Desktop version previously. It is installed on the hard drive of your computer either by download or with a CD. If you previously used Desktop, and want to transfer your prior year information into your 2018 return, you will need to use Desktop again. For more information, and to purchase a download or CD, see:
TurboTax Desktop
Products Comparison
For the Online version, see
TurboTax Online
Products Comparison