From my personal experience, you can win it from villagers during Festivale, and you sometimes find it in eggs you dig up from the ground during Bunny Day. I've heard you can obtain it somehow during Halloween, but since I haven't played CF during Halloween yet, I'm not exactly sure how.
Just so you know, unlike GCN and NL, there are four types of candy. Red candy, yellow candy, green candy, and blue candy. You have to give Pavé a certain type during Festivale, but other than that I think there's no difference between the four. In GCN and NL, there's only the yellow candy, and it's simply called "candy".