To do your taxes for prior years, you will need the tax software for
those years. TurboTax Online is only available for the current year, however, you can purchase the CD/Download versions for prior years here to prepare your returns for the past 3 years:
Prior year TurboTax Products
Prior year
tax returns cannot be electronically filed, however once you have
prepared your return using TurboTax, you can print out a copy to mail to
the IRS.
