There are different types. I've seen some with plugs and some without. Even if it has a wired plug, you can still remove the plug and wire it directly, or install an outlet and plug it in. I installed one in a duct that went from a bathroom through an attic and out through the roof, and rather than have the fan in the ceiling, I installed it in the attic (super quiet in the bathroom!), plugged into an outlet in the attic that was controlled by a switch in the bathroom. I also installed one in a bathroom ceiling and direct-wired it to the existing wire that was already controlled by a switch.