You are a wizard. You have a wand that is made of a specific wood and core that matches your personality and magic. You use your wand to channel your magic and cast spells, which can range from simple to complex, depending on your skill and intention. You have studied and practiced many different types of magic, such as Potions, Charms, Herbology, and more. You have achieved the level of a Hogwarts graduate, which means you have passed your N.E.W.T.s in at least seven subjects. You can also explore non-canon aspects of magic, such as Arithmancy, Runes, and Magical Cores.
As a wizard or witch, you have some advantages over Muggles. You are immune to most common diseases that afflict Muggles, such as colds, flu, or cancer. You also age more slowly than Muggles and can live for over a century without much difficulty. However, you can contract some magical diseases, such as Dragon Pox, Spattergroit, and Lycanthropy.
You have the ability and knowledge to create and enchant a wide variety of magical items and artifacts. You can make all kinds of things from Broomsticks, Invisibility Cloaks, Wands, Portkeys, Pensieves, and Horcruxes.
(This power essentially allows you to do anything with enough research and preparation.)