How to auto import the necessary classes in Android Studio with shortcut?

On my Mac Auto import option was not showing it was initially hidden

Android studio ->Preferences->editor->General->Auto Import

and then typed in searched field auto then auto import option appeared. And now auto import option is now always shown as default in Editor->General. hopefully this option will also help others. See attached screenshot

Go on the missing declaration with cursor and press alt+enter

Ctrl + Alt + O to optimize imports

Go to File -> Settings -> Editor -> Auto Import -> Java and make the below things:

Select Insert imports on paste value to All

Do tick mark on Add unambigious imports on the fly option and "Optimize imports on the fly*