Paintbrush

A paintbrush is a brush used to apply paint or ink. A paintbrush is usually made by clamping bristles to a handle with a ferrule. They are available in various sizes, shapes, and materials. Thicker ones are used for filling in, and thinner ones are used for details. They may be subdivided into decorators’ brushes used for painting and decorating and artists’ brushes use for [[visual_arts].
— Wikipedia

Computer graphics software, like Krita provides several tools for painting and editing image color. The Brush tool and the Pencil tool work like traditional drawing tools applying color with brush strokes.