While the video player is open, press on your Fire TV remote for Options. Click to enable or disable captions.
To customize your Fire TV captions, on your Fire TV menu click Settings > Accessibility > Closed Caption. From there, you can turn captions on/off, modify the text, color, etc.
Learn more about Fire TV accessibility features here.
While the video player is open, tap the gear icon on the top-right corner for Options. Click to enable or disable captions.
Learn more about Fire tablet accessibility features here.