Q.What is the cause of white anthuriums turning green?
I have been taking care if this white anthurium and I think it is already full grown. I’m still watering and taking care of it until the flower turns green day after day. What do you think is the cause of it? Should I cut it? If so, how do I cut the flower so it won’t affect the plant?
This is a perfectly natural part of the flower's cycle. Mostly they go from white to green to brown, although sometimes they skip one of the steps. I don't usually cut them until the flower turns brown, but you can cut them anytime. Just follow the flower stem down toward the bottom of the plant, and cut it off where it emerges from the leaves. This article has some more information you might find interesting: https://www.gardeningknowhow.com/houseplants/anthurium/anthurium-care.htm