When a photo is taken, a camera sound is heard as an acoustic confirmation that a photo has been taken. By default, the camera sound is activated on the Oppo Smartphone, but can be deactivated in the settings of the camera app.

Android 10 (ColorOS 7.0)
Step 1:  Open the  Camera-App
Step 2:  Open the  Menu
Step 3:  Open the  Settings
Step 4:  Enable or Disable  Shutter Sound
  1. Open the Camera-App
  2. Open the Menu
  3. Open the Settings
  4. Enable or Disable Shutter Sound

Oppo Instructions