When you first start up the game, you’re given the starter options of Charmander, Squirtle and Bulbasaur. But if you aren’t happy with those choices, there’s actually a way of getting Pikachu as a starter instead.
When those three starter Pokemon spawn in the beginning of the game, don’t select any of them. Instead, physically walk away from the area (in real life). As you keep walking, the same three starters will continuously spawn next to you. But if you keep on walking in the same direction and force them to spawn four times, Pikachu will finally appear as an option. It takes a while to actually get right, and it requires you to walk around aimlessly like an idiot, but Pikachu is worth it. Learn more about getting Pikachu as a starter in Pokémon Go here: