Can I just file State Tax Return through this website since I already filed Federal return through their website?

Not very easily, and not for free. With TurboTax you absolutely "MUST" complete a federal return at a minimum. Then for the state return many states will not accept an e-filed return until "AFTER" your e-filed federal return has been accepted by the IRS.

 The TurboTax State program is designed to transfer information from your federal return. For this reason, TurboTax State is not sold as a standalone tax-preparation product.

You can use TurboTax to prepare and file your federal return without your state – but not the other way around.

If you already filed your federal return outside of TurboTax and just need to do your state, you can either:

1. Contact your State Department of Revenue or visit their website to use their tax-filing service or to download and print out their tax forms; or
2. Re-create your federal return in the TurboTax software or TurboTax Online but don't file it. Then prepare and file your state return using TurboTax.
   • You'll need to paper-file your state return, as state returns cannot be e-filed separately.

The first option is free; the second option requires payment for both federal and state returns, even though you won't be filing your federal.