The Material Plane is made of physical matter and is home to all known mortals. Humans, Elves, Dwarves, Gnomes, and Orcs are indigenous to this plane. Fey and Tiefling both have heritage in other planes and are themselves made partly of magic.
The Algaian calendar dates the first civilization to 941 years ago, with the founding of Algaia. However, Elementals were marking the earth with arcane writing five thousand years ago. The world itself, many will tell you, came into existence when primordial Elementals found each other through the chasms of time and bound their bodies together into a world.
It is believed that magic and its many schools are the result of the Material Plane bumping into other planes of existence. The veil between the Feywild and the Material Plane can be poked and tugged on to create illusions and evocations. A similar invisible veil between the Abyss and the Material Plane is wet with necromantic magic. Those who learn to peer through the veil between the Fractal River and our world risk their lives for divination magic.
As far as anyone knows, this is the only plane of existence where thinking things can become no more. To be a plane defined by the “material” is to be defined by mortality.