Raichu is a Pokémon introduced in Generation 1.
Raichu-Alola, just like its Kanto counterpart, mostly functions as a Support Pokémon. It has a decently high Speed stat, and somewhat decent offenses; It's still rather frail, meaning that it cannot take hits from any powerful move that well. It can use strong moves like Endeavor, Fake Out, Thunder Wave and others, and Helping Hand, but under Electric Terrain, its speed doubles, which causes it to outspeed most other unboosted Pokémon on the field. It can also use Psychic Terrains to fire off strong STAB-boosted Expanding Forces.
As Raichu-Alola is a Electric/Psychic type, it's weak to Ground, Bug, Ghost and Dark, and is immune to paralysis.