how to fix the iphone microphone already used By another app

Hi bhram97,

Welcome to Apple Support Communities. We understand that you're having an issue with the microphone on your iPhone. We'd like to help.

It looks like you may be running iOS 13 on your iPhone 7. There have been some updates to the iOS that can help with issues like this. This resource can help you back up your data and update:

Update your iPhone, iPad, or iPod touch

If updating doesn't resolve the issue, please reply with a few more details about what you're experiencing with the microphone:

-Is your microphone working with some apps but not others?

-Are you experiencing any issues with your microphone while on a call?

-What exactly is happening with your microphone?

Hope that helps!