Radio is just a type of invisible light. We don’t have to “harness” a bunch of light waves floating around in the air to power our light bulbs - we make more light directly. Same thing for radio.

Think of it this way. If you want to talk to your friends with flashlights, you can turn them on and off in morse code. Likewise, a cell phone tower is sort of like a big “radio lightbulb” and it blinks really fast to communicate with your phone’s “radio camera”. Your phone translates that blinking it sees into information. (Oversimplified but vaguely how it works.)