Earth is moving three ways at the same time.  One, the earth is spinning on the axis called rotation; one full rotation is one day.  Two, the earth is orbiting the sun; one full orbit is a year.  The earth and the rest of the solar system are also orbiting the center of the Milky Way Galaxy.

The Earth is rotating on its axis.
 

The Earth is orbiting the sun
.

The Earth, Sun and the rest of the solar system is orbiting the center of the Milky Way Galaxy.
 

Newton First Law describes the Earth’s rotation by stating, once in motion the Earth will stay in motion unless acted on a net force.  The orbiting is explained by the net force acting on the Earth.  The Earth has momentum to move away from the Sun (called a horizontal force) at the same time the Earth is falling toward the Sun (called a vertical force).    The two force acting on the Earth causes the acceleration of the Earth move in the orbit.  As an example place your right arm out to the side and place the other in front of you, so you have a 90 degree difference, try to follow both at the same time.  You have to step between the two, resulting in you acceleration alone the net force.   In summation the Earth is moving three different ways at once it is rotation on it axis, orbiting the sun and orbiting the galaxy with the rest of the solar system.