How do I change the color of objects on a page?
You can select a color for handwriting, text, highlights, and shapes using the color picker before drawing/writing.
To change the color of handwriting, text, highlights, and shapes that are already on the page, you must first select the object(s). Then tap the color picker (
) at the top of the screen, and select a color for the object(s) you selected.

For a video tutorial about changing the color of objects, see Squid - Tools Overview.