AirPods microphones can be used for a variety of tasks, including making and receiving phone calls, recording voice memos, and dictating text.

To make a phone call using your AirPods, simply tap the stem of either AirPod to answer the call. To end the call, double-tap the stem of either AirPod.
See more: https://barcodelive.org/how-to-clean-airpods-microphone