In the player's menu
Subtitles and dubs live in the player of the service you open with Watch now. Look for the speech-bubble or the gear icon: the subtitle menu lists every language the service carries for your country, and the audio menu beside it lists the dubs.
What to expect
The big releases usually carry a long list, English, Spanish, French, German, Portuguese, Hindi and more, and the family films are often dubbed into many languages. The international titles on DogeFlix, Sky Rojo from Spain or Demon Slayer: Mugen Train from Japan, come with English subtitles and, on most services, an English dub.
A different service, a different list
When the track you want sits on one service and not another, try the next service in the Watch now list; each one carries its own set.