I completely love this question.

The courts of the late Middle Ages used an absolutely mind-blowing amount of lighting--individual tapers, full candelabras and chandeliers, larger torches when brighter light was culturally significant. (For example, on either side of the altar at Mass, or using twice as many to light the duke of Burgundy's dining table as the table of his relatives/rivals.) To give just one example, when Edward I lay in state following his death in 1307, the royal household purchased 843 pounds of wax for candles to surround his body. A minor court official under him would still receive a candlelit wake of 300 candles. Yes, supplied by the royal family--in fact, distribution of candles as gifts/livery to court members was a major drain on medieval royal wax resources.

When it came to acquisition of necessary goods in late medieval royal courts, Malcolm Vale argues that it was almost always the case that the king relied upon a group of outside merchants for the supply, rather than having designated "court artists" to provide e.g. furniture or tapestries. (Often, though, the same names appear in records at numerous points in a king's reign, suggesting the existence of favorites/known reliable workers to turn to). It was little different with candles.

Responsibility for the acquisition of candles and related goods in the court culture orbit of late medieval Burgunday-France-England generally lay with a designated official of the king's household. Often candles, specifically, were the responsibility of someone with another central task--but not always the same task. French king Philip the Fair, for example, had a specific staff dedicated to making sure fruit, dates, and nuts appeared on all tables at meals. One or more of these fruitiers was responsible for the acquisition of "candles and wax" and "great torches." And not just for meals, either. Household accounts often add "for the chapel" or "for the Mass-altar" or some such.

Meanwhile, under Henry III of England, a goldsmith actually seems to have been in charge of candle selection! Edward Fitz Odo was an "ascended craftsman" of sorts--he was actually responsible for overseeing a lot of the artistic-type needs of the court. He would find and hire painters for ever-more elaborate decoration of the royal chamber (four Gospel authors for four walls, amirite?)--and sometimes, it seems, for new construction on the castle. Among Odo's responsibilities was, you guessed it, acquiring the candles needed to put on the proper show.

One thing I'm really intrigued by is the way many of the primary sources (quoted by Vale, and then a few I found via typing phrases in Google because that is how I roll) distinguish between "candles" and "wax." I'm not sure if this means that lump beeswax was acquired, at which point the household organizer would also have to have hired chandlers to finish the job; or if we are to make a distinction between wax candles and tallow candles. I would honestly assume the latter, except tallow candles are generally associated with middle/lower classes, being cheaper but less user-friendly. And if we're dealing with people who can burn down 843 pounds of wax for a dead body, cost is probably not the first factor on their minds.