E-paper is a kind of screen made to look like ink on real paper. The letters sit still, the surface does not glow the way a phone does, and it can hold the page even when the power is very low, so long reading is easier on the eyes — including outdoors in the sun. You meet it most in e-readers. People also say electronic paper. It is a tech-and-product word, not something you use in everyday chat unless you are talking about devices. Some speakers loosely say e-paper when they mean a newspaper’s website or a file instead of a printed page; that is a stretch. The careful meaning is the paper-like screen, not “any writing that is not on paper.”