No one is ever going to transform into a were-wolf using magic. EVER. At least not physically (I have no idea what you can do with spirit animals and the like).
Magic can bring you to your greatest potential, fix events in your favor, and pull joy out of the greatest of sorrows. It is powerful in that it connects one to the unseen and spiritual and allows one to influence events around them.
IT DOESN'T do the impossible.
Rearranging a person's DNA to hold incompatible chromosomes of a person and a wolf, having those be actually expressed, not provoking an immune response, surviving the internal bleeding and trauma of ripping bone, tendons, blood vessels, and muscle, as well as creating mass out of nothing to change the size and shape of a person turning into a wearwolf, ISN'T possible.
If you want to do something with wolves, you can work on totems, and things like that, on which I am no expert. You can maybe even make a spell to make it more likely to encounter a wolf or to take on some wolvish characteristics (Aggressive territorialness, slavish obedience to social structure, the ability to enjoy meat medium rare), but you can't become a werewolf a la Jacob in Twilight. Nor should you want to.
Werewolves have been described in mythology since roman times, as people who suffered a curse or made an ill-advised agreement which forced them to become uncontrollable beasts which attacked those around them.