There are two places you need to specify drawing colors. These are referred to as Drawing and Filling or sometimes Stroking and Non-Stroking.
A Brush is used for filling areas. The most common brush type is the solid brush which fills using one color.
However there are other types of brushes. For example a texture brush fills an area with an image. So, for example, you can draw an oval filled with a picture.
A Pen is used for drawing outlines. Pens have a color and also a size. By default this is one pixel but you can specify different sizes to draw thicker lines.
Pens can be quite sophisticated. You can change them to draw patterns like draw dotted or dashed lines. Similarly you can control how corners and end points are drawn.
A Font is used for drawing text. A font has a font family (e.g. Arial), a size and a style (e.g. bold italic). The color of a font is specified using a Brush and optionally a Pen.