Courier is a monospaced slab serif typeface designed to resemble the output from a strike-on typewriter. The typeface was designed by Howard "Bud" Kettler in 1955, and it was later redrawn by Adrian Frutiger for the IBM Selectric Composer series of electric typewriters.
Although the design of the original Courier typeface was commissioned by IBM, the company deliberately chose not to secure legal exclusivity to the typeface and it soon became a standard font used throughout the typewriter industry. Since IBM deliberately chose not to seek any copyright, trademark, or design patent protection, the Courier typeface cannot now be trademarked or copyrighted and is completely royalty free.
As a monospaced font, in the 1990s, it found renewed use in the electronic world in situations where columns of characters must be consistently aligned. It has also become an industry standard for all screenplays to be written in 12 point Courier or a close variant. 12 point Courier New was also the U.S. State Department's standard typeface until January 2004, when it was replaced with 14 point Times New Roman. Reasons for the change included the desire for a more "modern" and "legible" font.
Kettler was once quoted about how the name was chosen. The font was nearly released with the name "Messenger." After giving it some thought, Kettler said, "A letter can be just an ordinary messenger, or it can be the courier, which radiates dignity, prestige, and stability."