XP stands for experience. 5 XP points are needed to level up.
Main characters gain experience when they
- Participate in a battle
- Make progress towards their dreams
- From their unique mechanic on their playbook.
Pokémon gain experience when they
- Participate in a battle
- Solve a Problem
Characters can always earn XP at the whims of the GM, too. Here's some unofficial, Homebrew ideas for XP, depending on the types of stories you're trying to tell.
- Release a Pokémon to an objectively more healthy and enriching environment.