Guide: How to Level-Lock
How-to Level-Lock a Pokemon
To level-lock a pokemon, start by opening your inventory, and right-clicking the pokemon you wish to level-lock.
In this summary window you will find lots of information about your pokemon, but what we are interested in right now is the little ‘L’ Symbol near the top, just above where it states the level of your pokemon.
Hit yes, to accept, and you’re done! Follow the same steps to unlock your pokemon’s experience gain.