Here are some steps and things to consider when dealing with background noise from your phone’s microphone:

1. Clean the microphone – Wipe the microphone with a dry cloth to ensure the microphone is not blocked.
2. Check for outside interference – Check if there’s any interference from wireless devices like routers, WiFi networks, cordless phones, etc.
3. Adjust the environment – If possible, adjust the environment to reduce echo or other noise sources.
4. Check your settings – Check audio settings like noise cancellation and echo cancellation.