Color Fills
A color fill fills a shape with a single solid color. It’s the default fill when you create a new shape.
Click the color swatch on the fill card to open the color picker. The alpha (transparency) can also be set from this color picker or by changing the A channel separately.
The R, G, B, and A channels are keyframeable individually, so you can animate a shape from one color to another without touching its shape or transform.