Broadly interpreted, solar power is simply turning the sun’s energy into usable power. There are a couple of mechanical processes. You’ve probably seen black pipes on roof tops that heat up water for swimming pools. You may have heard of, or seen pictures of those giant mirror arrays, using focused sunlight to heat liquids that turn turbines, making electricity.
Then there’s photo voltaic, which uses photons or light particles to bump electrons into action. When you move enough electrons in an organized fashion you’re making electricity. Solar panels are made from materials that allow photons to efficiently activate electrons.