Adjust Call Volume on Apple Watch
There are a few ways to adjust the volume during a call on your Apple Watch:
1. Turn the Digital Crown to adjust the volume up or down. This is the most direct way to control the volume while on a call[1][2][3].
2. Tap the volume down button in the Settings app under Sounds & Haptics to decrease the volume, or tap the volume up button to increase it. You can also tap the slider and rotate the Digital Crown[4].
3. If you're having trouble hearing the caller, make sure you are not in Silent Mode. Open the Settings app, go to Sounds & Haptics, and ensure the volume slider is set to an audible level[4].
4. If adjusting the volume with the Digital Crown has no effect, it may be a bug. As a workaround, you can switch the call to your paired iPhone and adjust the volume there[3].
5. For best results, wear your Apple Watch snugly so the back has good skin contact. This will ensure you can feel the haptic feedback when adjusting the volume[4].
So in summary, the easiest way is to simply turn the Digital Crown up or down while on an active call to control the volume. If you need to adjust it further, use the Settings app or switch to your iPhone if the watch volume isn't working as expected.
Citations:[1] https://discussions.apple.com/docs/DOC-250007577
[2] https://support.apple.com/en-nz/guide/watch/apd32b6c5658/watchos
[3] https://discussions.apple.com/thread/254582492
[4] https://support.apple.com/en-in/108368
[5] https://www.youtube.com/watch?v=veFquvezFts
[6] https://support.apple.com/en-au/guide/watch-ultra/apdc38d7a95e/watchos
[7] https://support.apple.com/en-gu/guide/watch/apd62807a9f3/watchos
[8] https://discussions.apple.com/thread/7062554