AirPods Pro
Press and hold the force sensor on the stem of an AirPod until you hear a chime.
When you're wearing both AirPods, press and hold the force sensor on either AirPod to switch between Active Noise Cancellation and Transparency mode. You can
customize which modes to switch between (Active Noise Cancellation, Transparency mode, and Off) in Settings.
To use Active Noise Cancellation with one AirPod only, use your iPhone or iPad to go to Settings > Accessibility and turn on Noise Cancellation with One AirPod. Then press and hold the force sensor to switch between Active Noise Cancellation, Transparency mode, and Off.