Early keyboards were manufactured with keycaps and key switches as one unit. Later, with the introduction of overlay keyboards, the keycap became a separate component so that it could be placed in the user's desired location. In order to increase their usability, blank keycaps are also available with no pre-printed label. This is especially useful for overlay keyboards. The lettering on keycaps is usually done either by stamping or by laser for durability.

Custom keycaps have become a popular computer modification, with keycaps available in a wide variety of colors and styles.