In order to set up Voice Isolation on your iPhone or iPad, you must be on a call in a supported app, such as Zoom or FaceTime; the feature isn’t visible outside of a call, which is why so many users have never noticed it.
1. Make a call on the iPhone using an app like FaceTime.
2. Once you’re on a call, a green dot will appear in the top right corner of the screen. Swipe down from that corner to open the Control Center.
3. Two buttons should be visible above the Control Center: Video Effects and Mic Mode. Tap the Mic Mode button to open its menu.
4. In the menu, tap Voice Isolation. This will switch the call from its default Standard mode to Voice Isolation.
5. Swipe up to close the Control Center.