This asset is designed to display the microphone input level on any device: personal computer /PC, Mac/, mobile /Android, iOS/, tablet /Android, iOS/ and other. After installing this asset, open the demo scene "DemoSceneWithMicrophoneInputLevel" to see how the asset works. In the "Prefabs" folder there is a prefab that you can simply drag to the working scene and the device to display the microphone input level will appear on your scene. To configure anything not necessary, after start-up scene is prefab from work.
p.s. you can buy this asset in Unity asset store: https://assetstore.unity.com/packages/slug/140463