How to return $data to modal btn form (for Edit function)

Hi, i'm new with php and i wonder anybody here can help me with how to return data to a modal button.
when calling the edit button a page, it is quite easy as you just have to load the $data array in the controller that leads the view.
But with the modal button, there is no loading view, then where are loading the $data.

Please need help i'm stuck with my project work