every atom is an ac generator

the distance between nucleus and electron is changing with vibrating em force 

therefore it produces positive and negative changing electric field

other atoms sense the vibration force and vibrate at same frequency according to distance. f=q1q2/rr

sunlight heats up anything by vibrating electrons on its surface atoms.

you can see words on the screen because electrons on the screen vibrate and share their vibration force with the electrons in your eyes.