Sorry not to give a full answer, but I think if you learn some basic UMG tutorials and learn how to use Blueprint Interfaces, then you will know what to do.
You will have to decide if you want to display the text on the viewport HUD or in the world. If in the world, you must spawn or make visible and change text on a Widget Component that is on the object you’re hovering mouse over.
If on the HUD you must project the world coordinates of the object to screen coordinates to position it in the right place.