Writing instrument is a broad term that can refer to any tool used to create written works. The two most common writing instruments are the PEN and the PENCIL. A PEN is a handheld device used to apply ink to a surface, usually paper. It typically consists of a metal nib or ballpoint tip attached to a barrel containing ink. A PENCIL is a handheld device used to draw or write on a surface, usually paper. It typically consists of a graphite core encased in a wooden or plastic casing.