The Sun does not rotate around the Earth; rather, the Earth orbits around the Sun. This orbital motion of the Earth around the Sun is what causes the changing seasons and the cycle of day and night.
The Earth completes one orbit around the Sun approximately every 365.25 days, which defines a year. This orbital period is what gives us our annual calendar year. As the Earth orbits the Sun, it also rotates on its axis, causing day and night. The combination of these two motions results in the changing seasons and the patterns of sunlight and darkness that we experience on Earth.