Why does my iPhone 7 makes the shutter sound when I take a picture? I tried every option on the internet?

My stepson has one and it doesn't do it!

Hmm… Should've got a Samsung.

It's just a software gimmick, to give the picture-taking process a more 'realistic' experience. It is typically a feature of the camera app. If you don't like it, you can probably find alternate camera apps without the feature (or with a setting to turn sound on/off).

Many people find the 'click' useful to confirm that the shot was actually made, especially helpful in delayed exposures or multiple exposures.

The sound's volume is connected to the music/video volume, so you could mute the phone if it's important.

See if your stepson's phone is set to take 'live' photos, those mini-movies. The shutter sound is disabled for those (maybe to avoid distracting the subject?).

Use a wired headset, sound is silenced. Even if it's a dead pair of headphones.

It may depend upon which country your phone was sourced from.

In some countries (one example is Japan) the shutter sound is legally required at all times and can't be muted or disabled without modifying the phone hardware.

It's an attempt to make it much more difficult for perverts to take stealthy upskirt photos or similarly invasive and exploitative images.

You could use the silent switch to mute all the sounds, including the camera shutter, unless you have one from Japan which due to government regulations can't have that camera shutter silenced