I just learned today that the iPhone comes with an electronic scale function!
But it only supports 3Dtouch models.
It’s very simple. Open Settings, then find Accessibility, choose Touch and open 3D Touch.
Search touchscale through Safari, and enter the website.
TIPS: It only supports conductive items, things like plastics and ceramics will not be responded to.
The currently supported models are probably iPhoneXs Max, iPhoneXs, iPhoneX, iPhone8 Plus, iPhone8, iPhone7 Plus, iPhone7, iPhone6s Plus, and iPhone6s.
John Shen 
Sean Lee 
Tech leakers 
Molly A