how did sasuke get rinnegan

Sasuke Uchiha obtained the Rinnegan after receiving half of Hagoromo Otsutsuki's (Sage of Six Paths) chakra. This happened when Sasuke was near death during the Fourth Great Ninja War, and Hagoromo, seeing the potential to stop Kaguya's threat, granted him the Yin half of his Six Paths chakra. This chakra evolved Sasuke's left Sharingan into a unique form of Rinnegan marked by six tomoe. Sasuke already possessed the Indra chakra as the reincarnation of Indra Otsutsuki, and the infusion of Hagoromo's chakra awakened the Rinnegan in one eye. The other half of the chakra was given to Naruto Uzumaki, which is why Sasuke only has one Rinnegan. This Rinnegan granted Sasuke powerful abilities, including space-time ninjutsu and chakra absorption, making him among the strongest ninjas. Later, Sasuke lost the Rinnegan due to injury in a fight but initially gained it through this divine legacy and chakra gift from Hagoromo.