Meteors from Mars arrive on Earth as the result of impacts on the planet by other bodies, which launch material out into space. Some of this debris is pulled in by the gravity of the Earth, falling as Martian meteorites.
Throughout the solar system's history, all of the planets have been struck by comets, asteroids and even other planets. When this happens, some of the material falls back onto the planet, while some may go into an orbit around the planet. If an impact is large and violent enough, still more material can be ejected outside of the gravitational influence of the planet. This is how meteors from one body, such as the moon and Mars, arrive on the surface of another planet, like the Earth.
Many scientists speculate that water and even life itself may have come to Earth from a Martian meteorite, carried here inside or on a chunk of the Martian crust excavated by an impact. Of the many different types of meteorites found on Earth, only a small number are from Mars. Recent data sent back from Mars rovers indicates the provenance of these samples, showing that they are identical in makeup to rocks currently found on the surface of Mars.