A pen is a writing instrument which applies ink to a surface. Pens range in colors, but are mainly found with black and blue ink. Pens may be categorized by the kind of tip on them. The main modern types are:

ballpoint pens,

fountain pens,

rollerball pens,

marker pens,

Technical pens,

Space Pens, and

Mechanical pens.

There are two basic types of the ballpoint pen: disposable and refillable.

A power load that was very similar or the same as the ballpoint pen was developed by the Hungarian journalist Laszlo Biro. Biro developed a new tip consisting of a ball that was free to turn in a socket. The word used for ballpoint pens in Argentina is birome because Laszlo Biro lived there for many years; also, biro can be used to refer to a ballpoint pen in British English. It was originally invented for the British RAF, as problems occurred with fountain pens due to the low air pressure aboard planes in flight.