If you are using this on the screens in Method, then you can use one of our action which is called Character Function Action.
The Character functions action provides a way to manipulate and parse text.
In each function, there are parameters to specify the source of the text. Since text can be stored in a variety of different places within Method, a dropdown is provided to locate where the text is stored. This can range from text being manually typed in, to text being stored in action results or controls on screen.
You can read about it more here.
Find in JSON action is part of the Character Function action and something you are looking for.
Hope this helps!