i cant find flashlight on iphone X

It should be on Control Center.

Use and customize Control Center on your iPhone, iPad, and iPod touch - Apple Support

Regards

Giulio

The standard Flashlight is not an app, but it is available on the lock screen (bottom left) and in Control Center (also near bottom left, unless you added a lot).

It's not where?

It's not on your lock screen? It should be there, across from the camera icon.

It's not in your Control Center? Visit Settings > Control Center and enable it there.

You don't need a separate app to use the camera flash as a flashlight on the iPhone X. You should be able to use it from the lock screen unless you have disabled it there. You can also enable it in your Control Center if it is not there.