In TurboTax Online, you would report this interest on Form 1099-DIV. You will enter the total amount of interest income as shown on your 1099-DIV in box 1, then check My form has info in other boxes, and enter the Tax-exempt interest in Box 8.
Further in the interview, you will see a screen Tell us more about your tax-exempt interest, and you will be able to indicate which state or states the interest came from.