This article explains how to play PS1, PS2, and PS3 games on a PS4 by downloading or streaming them on PlayStation Plus, or by purchasing classic and remastered games from the PlayStation Store.
I made my PS4 backwards compatible!! (About time…)
The PlayStation 4 drive and hardware can’t read PS2 or PS3 discs, so the easiest way to access your favorite old games is with a PlayStation Plus Extra or Deluxe membership. The Extra tier includes access to the Game Catalog, which includes some PS4 titles. The more expensive Deluxe tier also includes the Classics Catalog, which includes older titles.
Some PS1, PS2, and PS3 games are available to purchase through the PlayStation Store, so you can play them on your PS4. There aren’t many available through the service, but they’re worth checking out. Here’s how to download them.
On your PlayStation 4, select the PlayStation Store icon and press the X button on your controller.