How to enable splitscreen mode in Elden Ring (single PC multiplayer)?

Rise, Tarnished, and be guided by grace to brandish the power of the Elden Ring and become an Elden Lord in the Lands Between. A vast world where open fields with a variety of situations and huge dungeons with complex and three-dimensional designs are seamlessly connected. As you explore, the joy of discovering unknown and overwhelming threats await you, leading to a high sense of accomplishment. (Steam) #multiplayer