Question: where to get a shiny charm in pokemon sun?
Answer: It seems the only way to get the shiny charm is by completing the Alola Pokédex, which is made up of four smaller sub-groups: The Melemele, Akala, Ula'ula and Poni Pokédexes. Once you catch all those Pokémon, visit the character on Heahea City named the game director.