If you did not file a federal return with TurboTax, you are not able to e-file just the state in TurboTax since it pulls information from the federal return. So if you have filed federal with another tax preparer, you can do one of the two options listed below.
NOTE: If you have already filed your federal return with TurboTax, you can just log back in and go to File tab and file your state return. The federal return must already be accepted by IRS in order to e-file the state return.