How to Catch Scatterbug and Vivillon in ‘Pokémon GO’

Collecting Scatterbug candy works the same as it does for other Pokémon in Pokémon GO. You can get more Scatterbug candies by catching more Scatterbugs, transferring those you don’t want to keep to the professor, or selecting a Scatterbug to be your buddy and walking with it.

You’ll need 25 Scatterbug candies to evolve Scatterbug into Spewpa, and then you’ll need an additional 100 candies to evolve it to Vivillon. In total, there are 18 different Vivillon patterns to collect.

Source: https://www.distractify.com/p/how-to-catch-scattterbug-pokemon-go