Question: how to evolve eevee into sylveon x?
Answer: Sylveon is a Fairy-type Eevee evolution, first introduced in Pokemon X and Y. Increase Eevee's Friendship to three-hearts and level it up when it knows a Fairy-type move to evolve it into Sylveon. If you take it to the friendship checker in Hammerlocke, he will say "You two get along great!