How do I get rid of subtitles on apple tv

On third party devices with the Apple TV app,

there is a default setting for closed captioning in Apple TV app Settings ⚙﹥Accessibility﹥Subtitles and Captioning﹥Closed Captions and SDH﹥On

or it may follow the device settings.

During playback, you can press the down button on the smart TV or device remote to show the Subtitles pane, then select an option (Off, or a language).

Apple TV app user guide for smart TVs and third party streaming devices - Apple Support

Change subtitles or languages for videos in the Apple TV app or iTunes Store - Apple Support