What is an artificial harmonic on guitar?
Guitarists are not limited to only those harmonics that naturally occur at nodes along the open strings. Harmonics can be produced while strings are fretted, too. Doing so allows you to chime harmonics not otherwise accessible. When harmonics are produced in this manner, they're called artificial harmonics.
How do you do artificial harmonics?
To produce an artificial harmonic, hold down a note on the neck with one finger of the non-dominant hand and use another finger to lightly touch a point on the string that is an integer divisor of its vibrational length. Then pluck the side of the string that's closer to the bridge.