Toph is a character from the cartoon Avatar: The Last Airbender.
In Avatar, there are four nations: The Air Nomads, the Water Tribes, the Earth Kingdom, and the Fire Nation. Some people are benders of their respective element(air for Air Nomads, water for Water Tribes, etc.), although most people lack the ability to bend. Bending is essentially being able to manipulate whatever element it is. As Toph is an earthbender, she can control earth. She learned earthbending from the creatures that invented it--the badgermoles. As such, she has a very deep understanding of it, and is the self-proclaimed best earthbender in the world. Although she is self-proclaimed, her actions show that she is without a doubt the best earthbender.
Seeing with her feet
Even though she's blind, she can "see" with her feet. She feels the vibrations in the ground to see what's around her. If something is in the air, she can't "see it", and she sees better when standing on solid ground. Everything's fuzzy on sand, until she learns to sandbend around season 2 episode 10.
Toph can not only bend earth, she's such a good bender that she can bend metal using the small amounts of minerals in metal. She's the first person to ever bend metal, and the best at it. As mentioned earlier, she also learns to bend sand.