As the earth orbits the sun, the sun’s rays strike the areas near the Equator at a more direct angle.
This delivers more energy at the equator, than they do at the poles.
It also means the poles are generally colder than the equator.
When sunlight shines on the earth at a lower angle, the energy of the sunlight is spread over a larger area, and is therefore weaker than if the sun is higher overhead and the energy is concentrated on a smaller area.
The axial tilt of the earth also causes the different seasons at the northern and southern hemisphere.
The hemisphere that is currently tilted toward the Sun experiences more hours of sunlight each day during the summer.