Given Rey's lineage as Palpatine's granddaughter, it is also reasonable to assume she is already better attuned to using Force Lightning than the average Force user, with Ben telling Rey that she has all of Palpatine's power within her at the beginning of The Rise of Skywalker.
While Jedi could create Force lightning, like Sith, they choose not to use that power due to its association with the dark side and immoral nature. Despite being equally as strong in the Force, one innately Sith ability that Jedi in the Star Wars franchise do not wield is Force lightning.
Darth Vader can not use force lighting, because of his severed arms. Robotic hands can't summon the force lighting. However Darth Vader can still use other forms of the force, such as force choke.
Did Rey use force lightning or electric Judgement?
During the mission to Pasaana, while battling Kylo Ren, the Jedi Rey released a burst of Force lightning so powerful it was able to obliterate a First Order troop transport ship.
Admittedly, Rey skills couldn't possibly be as developed as Anakin's or Luke's. Nevertheless, considering how fast of a learner she is, and how unique the powers she possesses are, it's not a stretch to say that Rey could be a more powerful Jedi than Anakin and Luke Skywalker.
Why Rey "Accidentally" Using Force Lightning Is So INFURIATING
Can only the dark side use Force lightning?
Force lightning ability was not restricted to dark-siders. Jedi and other light-siders who were strong of will and character could learn this power without falling to the dark side—but its use was viewed as inherently corrupting, and most Jedi Councils forbade its use.
Dooku first used Force lightning at a young age. According to the audiobook, Dooku: Jedi Lost, he was once abducted for a Dark Side ritual, conjuring lightning to kill his captors and escape. Dooku went on to become one of the greatest Jedi masters, but his ability to use lightning was seemingly a natural talent.
What is the most powerful form of Force lightning?
While Palpatine's lightning is by far the most powerful thing seen in the Star Wars movies, the Son's red lightning is certainly more dangerous. It's only been used by one other character in Star Wars canon, and that character was none other than Darth Vader.
The way of the Sith may be for the apprentice to kill his master, but there was no way Darth Vader would've ever beaten Emperor Palpatine in a fight prior to Return of the Jedi. Darth Vader's electronic suit is very susceptible to electricity, and Palpatine is known for his uses of Force lightning.
Yes he does enjoy the fight and is more aggressive with the form, but at no point does he actually use the dark side. The thing about Vapaad is that Mace uses himself as a conduit to redirect his opponent's dark side power back at them. So he isn't drawing on the dark side or using it himself.
While on the floor of the Senate, looking up at the cackling Emperor above him, Yoda clearly realized that he couldn't beat Palpatine in one-on-one combat. As considerable as his own power in the Force was, Palpatine's at that moment was even greater, and to continue fighting would likely only result in his demise.
Luke didn't need to be warned about force lightning. He had a very different form of training than Jedi just years earlier had. He was trained with self-experience, and that was truely what was best for him.
He tried, but was unprepared for the sheer power of Sidious' blast. It was magnitudes of order more powerful than Dooku's lightning, and it overwhelmed the defenses Yoda tried to throw up against it. Yoda just had no idea it would be so much stronger than what Dooku was able to muster.
Anakin is supposedly more powerful than other Sith Lords like Dooku yet he can't use force lighting. Any explanation? He can do it, but it would risk shorting out his life support. Here's an explanation from The Stupendous Wave.
Either way, while Vader can use most other Force abilities, Force Lightning needs to be channeled, and Vader's limbs are explicitly not connected to the Force. The Star Wars: Episode III - Revenge of the Sith Visual Dictionary confirms Darth Vader cannot use Force Lightning, and even suggests this is the reason why.
However, despite their strict adherence to the light side of the Force, several Jedi were known to use this power, as although it was considered a dark side ability, it was also a technique of telekinesis. Its use, however, was forbidden by the Jedi.
Likewise, the old man also shares that the end of the war saw him being hit by lightning before falling from a tower, the same way Mace Windu met his alleged demise in Revenge of the Sith at the hands of Palpatine. However, the shogun survived despite going blind, receiving a vision to find a lost temple.
Sidious may have given Dooku the title of Darth Tyranus, but because the Jedi Order knew him as Count Dooku, greatly preferring to not indulge his role as a Sith, they continued to call him by that name.
As a result, Palpatine's face changes in Star Wars: Episode III - Revenge of the Sith because his dark side-induced mask was broken by the Force Lightning rather than the Sith lord actually being disfigured by his own attack.
Sith eyes really only appear in those actively giving themselves up to the dark side. Palpatine is regularly seen without them, and Dooku seems to be a rather composed individual, given his alignment. It seems they're not permanent physical changes.
Force lightning can be deflected and absorbed by a lightsaber, and select Jedi have proved able to neutralize the technique through the power of the light side.
Sidious rarely used these elegant weapons, preferring to manipulate events indirectly and in secret. He wielded two lightsabers against his renegade apprentice Darth Maul and Savage Opress on Mandalore, took up arms to battle the Jedi on Coruscant, and used one of his crimson blades against his enemies on Ryloth.
TL;DR: Palpatine used Sith Alchemy to disguise himself and then when the lightning deflected off Mace Windu's saber it caused the alchemical spell to break, revealing his true face and possibly damaging it further in the process.
