What would be a best approach to highlight only specific parts of an image in Unity. My image would be something like below example a grid with text and fields. Text can be separated but I would prefer it be part of an image. Also fields can be different colors and I could change opacity to highlight them. Problem is how to change opacity on only a specific field is that even possible do I need some custom shader if so can anybody point me to right direction.

How can I highlight only specific parts of an image in Unity?

My image would be something like the example below: a grid with text and fields. Text can be separated, but I would prefer it be part of an image. Also fields can be different colors and I could change opacity to highlight them. My problem is how to change opacity on only a specific field: is that even possible? Do I need some custom shader?