An audible buzz from a light is the sound of something vibrating at the frequency of the supply, and there are only a handful of things in a fixture capable of doing it. Working out which one is usually a matter of listening to where the noise comes from.
Older fluorescent fixtures with magnetic ballasts hum from the ballast itself, and the noise gets worse as the laminations loosen with age and heat. That is a fixture at the end of its life, and replacing the ballast or the whole unit is the only real answer.
With modern lamps the culprit is more often the interaction between an LED driver and a dimmer. A dimmer works by chopping part of each cycle of the supply, and the driver in the lamp has to smooth what is left back into steady direct current. Some drivers do this quietly and some do not, and the same lamp can be silent on one dimmer and noticeably buzzy on another.
Dimmer type matters here. Leading-edge dimmers were designed for incandescent loads and work by cutting the beginning of each half cycle. Trailing-edge dimmers cut the end, which suits electronic drivers far better. Fitting a trailing-edge dimmer rated for LED loads solves a large share of buzzing complaints on its own.
Minimum load is the other common issue. A dimmer built for a five hundred watt incandescent load may need forty or fifty watts connected to behave properly. Replace six sixty-watt bulbs with six eight-watt LEDs and the total load drops to well under that threshold, which produces flicker at low settings, a refusal to turn on cleanly, or a persistent buzz.
Manufacturers publish compatibility lists pairing specific lamp models with specific dimmer models, and those lists exist because the combinations genuinely behave differently. Checking one before buying twenty lamps saves a great deal of trial and error.
When the noise comes from the wall rather than the ceiling, that is the dimmer itself, and a fixture-side change will not fix it.
Enclosed fixtures add one more variable. A driver running hot inside a sealed dome ages faster and starts misbehaving sooner, so lamps intended for enclosed fittings are built and rated differently. Using an ordinary lamp in a sealed fixture often produces flicker and noise months after installation rather than on day one.
Background reading: Residential Electrical Repair