OlloClip has released a set of macro lenses for the iPhone 7 and iPhone 7 Plus. It includes lenses with 7x, 14x, and 21x magnification. Here are some sample images.
If you want to expand your lens choices with the iPhone 6 or iPhone 6 Plus you’re going to need to attach something to the existing lens. I put the olloclip 4-in-1 kit for the iPhone 6 and iPhone 6 Plus through its paces.