There are three places you need to specify drawing colors. These are referred to as Pens, Paints and Text.
Additionally a Canvas has a Color. By default all Canvases are white but you can change this. Note that when you first set the size of the Canvas, or resize it later, all the newly exposed parts will be erased and set to the Canvas color.
Pens not only have a color but also a size. By default this is one pixel but you can specify different sizes to draw thicker lines.
Text also has a font, a size and a style as well as its color. You can specify a particular size (in points) and a set of styles (e.g. 'bold, italic').
As well as painting with solid colors you can also paint with patterns or textures. You can specify a pattern by creating an image. This can also be a Canvas onto which you have drawn and then exported as an image. You then provide this image to your drawing operation via the drawing options.