Please set the "Default recorder" from the below path:
Setting path：
realme UI 7.0: Settings > Sound & Vibration > More > Recording device for Camera, select External microphone or Internal microphone
realme UI 6.0 & 5.0 & 4.0 & 3.0: Settings > Sound & Vibration > Advanced Settings/More > Default Recorder
realme UI 2.0: Settings > Sound & Vibration > Other Settings > Default Recorder
realme UI 1.0: Settings > Sound & Vibration > Default Audio Recorder
realme UI R & Go & S & T & U Edition: No option, but it will use the earphone mic to record video when the phone connects to the earphone
You can choose Auto select or Add-on
1. Auto select ：
1.1 Always use the phone's microphone to record sound when the earphone is not plugged in;
1.2 When a device capable of recording, such as an earphone with audio recording capability, is inserted, if a video is being recorded, the microphone is used to record the sound; if a video is not recorded, the earphone is used to record the sound.
2. Add-on：
2.1 Always use the phone's microphone to record sound when the earphone is not plugged in;
2.2 When a device with recording capability is plugged in, the device is used for recording by default.