The app I used for my drawing is called Sketchbook. This app has many brushes and erasers if you buy the full version, which I did. I first simply sketched out my drawing in the first layer, and then on another layer I started my shading. I usually do my shading with an airbrush brush. I also do my shading with just a basic pen brush on the app. For this drawing, I had eight layers. Three layers had shading and different color spots. I do this because it's easier for me to color and not get colors in spots they don't need to go. I also used some blending tools. As you can see in my drawing's eyes, I used three colors: a shade of purple, a pinkish shade and a darkish blue and I blended it together using a smudge brush. I then put more layers to fill in what I haven't colored and so on from there.