Mobile phones are a need for daily life, and you must have noticed that each one of them has a little hole near the flash and camera lens. But have you ever questioned what it is for or why it is there?
The tiny hole is neither a button, nor does it have anything to do with your camera or flash. The rear microphone is a tiny microphone. Along with improving the sound, it also functions as a miniature noise-cancelling microphone.
Further investigation reveals that the holes at the bottom of the phone near the charging port or the socket for the headphones are also for noise cancelling.