1. When shooting outdoors, use a microphone windshield to avoid wind interference. Some cameras also have a wind noise reduction function.
2. On the other hand, if you're shooting in an extremely quiet environment, there might be some background noise caused by the microphone and camera mechanisms. It's normal and not a malfunction, and some editing software can easily filter that out.
3. If you use an external microphone, check if:
   • It's a compatible model
   • It's firmly connected to the camera microphone input
   • The recording level is set to an adequate level (especially be careful to record too loudly)
   If you're still experiencing distortion or interference, test the microphone with a different device or try using a different cable to connect the microphone.