Brushes are a useful way of getting paint from the palette to the canvas. They are by no means the only way (The ceiling of the sistine chapel has many fingerprints where Michelangelo blended using his fingers rather than brushes on occasion.
However most of the time a good brush is the prefered tool for painting.
There are may different
artist brushes available, so sometimes it can get confusing. Here is a basic
guide to the types of brushes used for oil and acrylic painting.
Round Brush - Round Brushes are great for thick strokes
of even colour.
Filbert Brush - A flat brush with a curved tip. Allows you
to produce a variety of strokes without changing your brush.
Fan Brush - A fan shape makes this an excellent subtle blending
brush.
Rigger Brush - A rigger is a long slender pointed sable paintbrush
used for fine detail work. Riggers are only used with heavily diluted oils,
acrylics or watercolour paints.