If you are printing and mailing your taxes, see the filing instructions document that prints out with the paper copy of your return. You'll see the address in those instructions. For your federal return, you can also look it up at this IRS website.
How do I print and mail my return in TurboTax Online?
Or, if you was printing a copy of your taxes for your records and would rather e-file your tax return, please follow these directions:
How do I change from mail to e-file in TurboTax Online?