As you can see, much of the Pokemon evolutions readily available in the game at the minute are Mega Evolutions. These can just be attained throughout battle, changing the Pokemon into a much better one-- however just for one battle. Even if there are several phases in a battle, the Mega Evolution will need to be reactivated once again, making it helpful just for long, difficult battles. In order to attain a Mega Evolution in Pokemon Masters, you will need to use the Sync Move (that special move all sets have) whenever it appears. Just keep in mind that in many cases and particularly early in the game, you're better off using a Sync Move that offers damage to the enemy team and getting a Mega Evolution is a waste. Just later, when battles are harder these are beginning to be worth it.