Audio and subtitles are chosen in the player of the service Watch now opens, usually from a speech-bubble icon. The original soundtrack is always there; dubs and subtitles depend on the service and the country.
K-drama
Korean dramas carry English subtitles on every service that lists them, and the big ones, Squid Game and The Glory among them, carry English dubs as well. The Korean voices are worth trying first.
Anime
Anime carries Japanese audio with English subtitles, and the popular series add English dubs a few weeks after the Japanese broadcast.
English-language series
The American and British series carry English subtitles for the hard of hearing on every service, plus dubs and subtitles in many languages on the global services.
