How do I change the background color of the entire canvas?
First, make sure all objects are deselected. You can do this quickly using the select-all / de-select all button. Then tap on the Paint Brush icon and select colors, you will be able to see the new selected color being immediately applied to the canvas background. If you select the first button, the dark one with a light gray border, you will have a transparent background. Transparent is equal to a clear background.

If you are creating an icon, a logo or a cartoon shape drawing, we recommend using clear backgrounds.

It's important to note if your work contains transparency, you need to export it in PNG format, as JPEG does not support transparency and will render transparent areas as solid white.