Spoiler: you can’t directly! But there are three workarounds
Apple tries to simulate the experience of a snapshot camera when you take a picture in the Photos app on an iPhone or iPad by issuing a little click sound. Many of us prefer to avoid that sound.
Remarkably, there’s no click on/off switch in the Camera settings! Instead, you have one of three alternatives:
Enable Live Photo: If you’re hearing a click, you don’t have this feature turned on, which retains some still images from before and after the point at which you take pictures, providing some animation—and audio. If the click were on, it would be captured in a Live Photo. You can have Live Photo always on when you launch the Camera by enabling Settings > Camera > Preserve Settings > Live Photo.
