It is commonly believed that one needs to be a Juubi Jinchuuriki to awaken the Rinne Sharingan, as the Juubi had the Rinne Sharingan and Kaguya was the Juubi. However, Madara has stated that the tablet mentions that the only requirement to awaken it is for someone with the Rinnegan to approach the moon. After acquiring both of his eyes, Madara went to the moon to obtain the Rinne Sharingan, shortly after meeting Naruto and Sasuke.