Varying in size, shape, and specification, PADDs are often distinguished by the species of their manufacturer or user. United Earth and Federation Starfleet PADDs are generally flat and rectangular in shape, while Klingon and Cardassian PADDs are often more angular. Standard issue during the 22nd century, PADDs utilized by Starfleet were rectangular in shape, dominated by a large display screen taking up much of the surface area of the device. Small buttons were located just below the screen, most often grouped in two, at the lower right-hand side of the interface. Varying control button arrangements were used. Most often PADDs are used to display schematics, or subspace transmissions and are capable of wireless computer networking as well as playing movies, recording logs and audio playback.
By 2364, PADDs had taken on a smaller profile and, while some models still included one, the stylus was replaced by simple, touch-sensitive controls, generally located beneath a small, square-shaped display screen. Generally small and light-weight, the PADDs of the 2360s and 2370s are basically rectangular in shape and varied in size, proportion, and even color – ranging from gray and muted blue colors, to red. When struck with enough force, the screen of a PADD could be shattered resulting in shards sharp enough to cut Human skin. While the common function of Federation PADDs is most often straightforward data entry or data retrieval, some PADDs are capable of more artistic tasks. Some PADDs, often larger in size than most of their counterparts, are used to draw up schematics or to create composite images or artwork. PADDs are also capable of predictive text functions, allowing users to enter a small amount of data to achieve full words or even sentences. In addition, a stylus could be used for text entry. PADDs can also be used to order a site-to-site transport, sending text messages to other PADDs, and a wide range of other uses.