You can level up your Pokemon figures in Pokemon Duel by fusing them with rare metals or figures or by completing missions in Story Mode.
What Is the Purpose of Leveling in Pokemon Duel?
Leveling up your Pokemon allows you to increase the size of an attack by 1 (you pick the attack) and decreases miss by 1. Leveling increases the probability more in your favor. The max level is 5.
After leveling up your Pokemon, you will be prompted to select an attack to increase. You can press Recommended and it will suggest which attack you should increase.
You can rearrange previously expanded attacks each time a figure levels up by hitting Reset on the Disk Expansion screen. This can be performed for free up to level 5, otherwise it will cost gems.
If the game crashed while leveling up, you can reallocate points under Menu > View Figures > select Pokemon > Disk Expansion/Damage Reallocation (this option will be grayed out if you already allocated the points).