Camera sound

Camera shutter can be put off by switching off the Ring/Silent switch.

If the iPhone has been purchased from Japan then the Camera shutter cannot be put off. Similarly many countries do not allow shutting off Camera shutter sound.

I'm sorry if it was not completely clear: there are countries where you cannot mute the shutter sound. It's illegal. A shutter sound cannot be muted on iPhone purchased from that country.

Seems like you purchased your iPhone in a country where it's illegal and shutter sound should always be turned on.