Electric guitars are not inherently noisy. However, they can produce a certain level of noise when the strings touch the frets, which is known as fret noise. This noise is often intentionally used by guitar players for various musical effects.
But if you’re referring to the hissing or humming sound that you might hear when playing an electric guitar through an amplifier, that is usually due to interference from electronic devices, faulty cables, or single-coil pickups. This noise can be minimized by using better quality cables, keeping electronic devices away from the guitar and amp, or switching to humbucker pickups, which are designed to reduce interference.