In the Fourth Great Ninja War, Sasuke Uchiha, who was already the reincarnation of Indra Otsutsuki, met Hagoromo after he was in a near-death state. Just as with Naruto, Hagoromo gave half of his chakra to Sasuke, which led to his left Sharingan turning into a Rinnegan.
Another big question that fans have aside from, “How did Sasuke get his Rinnegan?” is why he only has one. The primary reason for this is because the Sage of Six Paths distributed his power evenly between Sasuke and Naruto. Therefore, there wasn't enough power to give Sasuke the entire Rinnegan.
The Sage of Six Paths, Hagoromo Otsutsuki was certainly the strongest of all the Rinnegan users in Naruto. Unlike the other Rinnegan which are Kekkei Genkai, his was considered to be a Kekkei Mora, meaning its powers surpassed a regular Rinnegan.
It is possible for a Sharingan wielder to awaken a new Rinnegan by obtaining Hagoromo's chakra, either by combining the chakra of his sons, Indra and Asura, to recreate his own, or by directly receiving it from Hagoromo himself.
The one who has the visual Dōjutsu Sharingan can awaken the Rinnegan by combining chakras of Ashura or his reincarnated one. In this case, since Naruto is the reincarnation of Ashura, Naruto doesn't have a Dōjutsu prowess or can't awaken even the Sharingan.
One of the Three Great Eyes in Naruto, the Rinnegan is the strongest eye of them all. It was first said to be wielded by Hagoromo Otsutsuki, the Sage of Six Paths. Using the Rinnegan, the user can learn any jutsu they want and they gain access to special abilities and techniques commonly known as the Six Paths Powers.
In order to awaken the Rinnegan you must have the Uzumaki clan chakra or have the Hagoromo Otsutsuki chakra. All Uzumaki clan Rinnegan users have different six path abilities.
Urashiki's blue Rinnegan allows him to transport himself into the past to redo events.
The Sharingan Eye belongs genetically to the Uchiha Clan but can be transferred. It can only be awakened by powerful emotions and tragic experiences. The Sharingan Eye is the genetic birthright of the Uchiha Clan of Naruto.
The Rinnegan is an almighty Dojutsu known to be the strongest of all the Three Great Dojutsu. Being the eye of a god, it's no surprise that Sasuke's Rinnegan is extremely overpowered.
The Rinnegan is an exceptional eye that not just anyone can possess. Hagoromo Otsutsuki, the Sage of Six Paths, was the first one to wield this eye in the Naruto story. Only by recreating his chakra can this eye be awakened.
The Rinne-Sharingan is the most powerful known eye in the entire Narutoverse. It s wielded by the Ten-tails, and the progenitor of chakra on Earth, Kaguya Otsutsuki. The Rinne-Sharingan has nearly all the powers of the Rinnegan, along with the ability to cast powerful Genjutsu known as Infinite Tsukuyomi.
Kaguya's nine tomoe Rinnegan sounds like the most powerful, since it can cast Infinite Tsukuyomi and Dimensional Shifting. About Sasuke's six tomoe Rinnegan and Hagoromo/Madara's purple Rinnegan, I think they're tied.
Just like Naruto, Sasuke also ended up receiving Six Paths powers from Hagoromo Otsutsuki after a near-death encounter. Unlike Naruto, he ended up receiving the Six Paths Yin power, marked by the crescent moon on his left hand. The Six Paths powers led to him awakening the Rinnegan in his left eye.
It's entirely possible that Sasuke's eye could recover over time, but if the series is smart then it'll be quite a while before he'd be able to do so. But there's a greater chance that Sasuke has lost his Rinnegan for good.
For the most part, Sasuke has used this ability sparingly due to the way it drains his chakra, as well as the element of surprise that is crucial to its success. Sasuke can also create portals to travel between dimensions with his Rinnegan.
Sasuke awakened his Mangekyou Sharingan early in life, and suffered the price of almost going blind. The Mangekyou Sharingan gives the user incredible new abilities, but every time it's activated, the user starts to lose their eye sight.
Itachi ended up giving Naruto the crow, which had Shisui's eye. Itachi later explained the significance of the crow to Naruto. He stated that he programmed the eye on the crow to use Kotoamatsukami on the person that takes Itachi's Mangekyou Sharingan.
As you can see above, the form Momoshiki took after eating Kinishiki gave him a different Rinnegan. Unlike the one Kaguya rocked back in Naruto: Shippuden, Momoshiki's Rinnegan is golden in color. So, you do not have to worry about getting his Dojutsu confused with anyone else's — well, for now.
The Rinne-Sharingan possesses an unfathomable amount of power, one that can neither be comprehended nor controlled by a regular shinobi. The only known users of this ominous power are Madara Uchiha and Kaguya Otsutsuki, who showcased this divine power's true potential.
The Rinnegan is able to see chakra and its flow within the body, as well as otherwise invisible barriers, but cannot see through obstructions such as smoke bombs. Possession of the Rinnegan allows one to easily master any jutsu as well as all five basic nature transformations.
1 WEAKEST: Ketsuryugan
While it is powerful, it doesn't stand a chance when up against the likes of the Sharingan or the Byakugan.
The reason why Madara picked Nagato is simply because he is a member of the Uzumaki clan. Therefore, he has the same innate physical abilities as the Senju, which makes him the perfect container for the Rinnegan.
Only those that have Ashura/Indra's chakra or Hagoromo's chakra can awaken the Rinnegan. That's why Obito didn't awaken his Rinnegan, simply because he isn't a reincarnate of Indra even though he had Ashura's DNA and didn't have Hagoromo's chakra.