How to make your UI fit any iOS resolution?

I am struggling with fitting my game into all the iOS resolutions. In the ios Simulator for iPhone 4s that camera is cut off. In iPhone 6 plus the camera is zoomed in the bottom corner(I’ve done some research and the problem is that the unity splash image is not correct). It is ok to make the screen look stretched or squished. Is there a way to make the things work for every resolution?

Use the Ui scaler Just Adjust the x & y but keep the match at 0.5