I don’t have live voicemail in phone settings on iPhone 13 pro or is this feature for iPhone 15

It should work on any phone that can run iOS 17. Live voicemail is only available in the US and Canada currently. It also requires that cellular data be turned on, as it can’t use Wi-Fi.

Also, the Live Voicemail does require your iPhone language to be set to English (as it's currently EN only).

See related article at top: Use Live Voicemail on your iPhone