How can I make Siri use non apple apps? [duplicate]
Solution 1:
This is currently not possible. Siri is only able to use Apple's standard apps, sadly.
Solution 2:
Siri only provides full integration with first-party apps and services on iOS.
However, should certain apps use public APIs which integrate with iOS, such as media apps which utilise the media playback API (usually noticeable by being able to pause/play from Control Center) then Siri will be able to perform simple tasks such as pause/play/next.
This still won't let you pick specific media by name as you can with the first-party Music app, but Siri does provide some integration with apps outside those created by Apple.