Here is a link with more information on how to file an extension through TurboTax.
This is an excerpt from the above link:
You may be allowed an automatic 2-month extension of time to file your return and pay any federal income tax that is due. You will be allowed the extension if you are a U.S. citizen or resident alien and on the regular due date of your return:
- You are living outside of the United States and Puerto Rico and your main place of business or post of duty is outside the United States and Puerto Rico, or
- You are in military or naval service on duty outside the United States and Puerto Rico