What specific screen and question are you answering?
Are you in the MY INFO section, and is it the screen that asks "Did you make money in any other states?"
I made a mistake and answered no. I should have said yes.
In my Answer below have provided a screen image on that question and how to indicate a non-US "state". You can step through the MY INFO section to change your answer, OR if you had finished that section, you may instead come to a Personal Info Summary screen. If you come to the summary screen, scroll way down to the last category where it says "Other state income" and click the small EDIT link to the right, and it will open that screen back up to make your change. See my answer and image below for the rest of the info.
I can't comment on any tax details specifically about Puerto Rico, other than to say that TurboTax cannot prepare a Puerto Rican tax return. But I can tell you how to indicate on that screen that you made money outside the US.
In the MY INFO section you can indicate that you made money in a "state" outside the USA. One of the choices is "Foreign or US Possession". Here's how to bring it up:
When you go through the MY INFO section, you'll come to a screen that asks "Did you make money in any other states?"
Or if you had already finished that section, then when you go back, you may get a Personal Info Summary screen instead. If so, then scroll down to the last category called "Other state income" and click the small blue EDIT button to bring up that screen.
If that's what you are referring to, see the screen image below.
There is a dropdown menu and when you scroll down below Wyoming, you'll see a choice "Foreign or US Possession."