To find out information about the spawn of a Pokémon, use /wiki [name]. This will give you information like:
- BIOME - the biome is spawns in, it's preferred spawn time, spawn weather, and spawn location
- RARITY - how rare the Pokémon spawn rate is (the lower the spawn rate, the harder it is to find)
- DROP - some wild Pokémon will drop items when defeated (not every Pokémon will drop something)