It's best to add pectic enzyme before fermentation, but you can add it afterwards as well. After fermentation you should add 2x the recommended amount, because alcohol prevents it from working as well. I have also discovered that pectic enzyme works better if it is a bit warmer, e.g. around 70-75 degrees F. If it is too cold it doesn't seem to do much.
My peach wine takes about 6 months to clear in bulk aging, so time helps as well. It depends on the cause of the cloudiness. I'm not sure that fining agents will clear pectic haze, but others with more experience with fining agents can address that.