The difference between these two is how a person aka a defendant is punished.
Criminal law: there are at least 3 forms of punishment for these defendants and they are jail, get fined, or death penalty.
Civil law: jail time and death penalty don't apply to this type of case. Defendants typically have to pay the plaintiff (aka person who filed the grievance against the defendant) what is due meaning the payment is based on what was damaged or lost.
Hopefully this helped somewhat and good luck.