Catch or evolve an Eevee
Set Eevee as your Buddy
Earn 70 Buddy hearts with that Eevee
Make sure Eevee is still your Buddy
Evolve Eevee during the day or night
Use 25 Eevee Candy to complete the evolution
If the name trick is still available for your account, rename Eevee to Kira before evolving it