点击屏幕后如何使用以运行代码？

I am working on a game in Xcode where an object is bouncing back and forth across the screen. I need to run the code to stop the object from moving once the user taps anywhere on the screen. I don't want to use a button although I could. I am new to this and don't understand what I need to use in order to run some code once the user taps the screen. Could you please tell me what to use and explain what it does. I am working on a game in Xcode where an object