I have my peace lily outside on a covered porch. When I bring it in for the winter, can I prune it back. If so, how far back and every leaf?

You only need to prune it back if you feel it is getting too large for the space you are going to put it indoors. I have never pruned my peace lilies before. I certainly wouldn't take all the leaves off. If it is not too large, then I would advise to just leave it alone.