Where is the sun rays strike earth most directly and least directly

The sun strikes the most at the equator. The sun strikes lowest at the poles.

The sun rays strike earth most directly at the equator and that's due to the Earth angle of rotation, that makes it possible for the sun to hit most directly at the equate.

The sun rays strike earth least directly at the poles and that's also due to the Earth angle of rotation., that's why the poles are colder than the equator.