How and what is the easiest way to root an arrowhead ivy?
I'm guessing that by arrowhead ivy you mean the syngonium. Take cuttings from the heavy vining stem, not leaf stems. Use cuttings that have at least one node (joint) from which the roots can grow. They are very easy to root, using almost any method - water, potting soil, perlite, etc. Try a variety, and use what works best for you. https://www.gardeningknowhow.com/garden-how-to/projects/rooting-plant-cuttings.htm