How do you make images like water droplet's refract or reflect on what the players screen sees?

Right now I am trying to make droplet's appear when a certain value turns on, to make a droplet appear on the screen of the player I have to create an image, so I got and image from google, but right now I don't know how to make it distort the inside of the droplet to make it look realistic, I looked through the properties and found nothing.