A desk was a table used as a working place.
The captain's ready room aboard United Earth Starfleet and, later, Federation starships included a desk, often equipped with a desktop monitor. (Star Trek: Enterprise, Star Trek: The Next Generation, Star Trek: Voyager)
The desk in Captain Jonathan Archer's ready room featured a slot to read a data module. (ENT: "Terra Nova")
Some quarters aboard Enterprise NX-01 were equipped with a desk including the quarters of Sub-commander T'Pol and Captain Jonathan Archer. (ENT: "Breaking the Ice", "Fortunate Son")
The shopkeeper Garos had a desk in his curio shop on the Akaali homeworld in 2151. (ENT: "Civilization")
While under the effects of trellium-D in 2154, T'Pol angrily struck the desk in Captain Jonathan Archer's ready room with a PADD which consequently shattered. Archer noted that, though they had repeatedly disagreed in the past, T'Pol had never before "taken it out on [his] desk." (ENT: "Damage")
Child-sized desks could be found in classrooms. (TOS: "Miri"; TNG: "When The Bough Breaks"; DS9: "A Man Alone", "The Nagus", "In the Hands of the Prophets")
Desks were often used to display objects of interest, such as silicon nodules – Horta eggs in reality. (TOS: "The Devil in the Dark")
The battle bridge ready room aboard the USS Enterprise-D also featured a desk. (TNG: "Encounter at Farpoint")
The Bandi Groppler Zorn had a large, wooden desk in his office on Deneb IV. (TNG: "Encounter at Farpoint") Karnas of Mordan IV also had a desk in his office. (TNG: "Too Short A Season")
Starfleet workplaces featured a special desk made out of wood and glass. Desks like this one were featured in guest quarters aboard the Enterprise-D in 2364 and offices at Starfleet Headquarters in 2372. (TNG: "Conspiracy"; DS9: "Homefront", "Paradise Lost")
Pe'Nar Makull had a glass desk in his hiding place on his homeworld. (VOY: "Time and Again")
In 2375, Starfleet officer Al Lorenzo collected holo-images of himself behind the desks of famous captains. (DS9: "Treachery, Faith and the Great River")