One UI 5

How To: Turn Your Samsung Galaxy Smartphone or Tablet into a Second Display for Your Computer

An iPad can serve as a second screen for a Mac via Sidecar, available since iPadOS 13, but Apple isn't the only manufacturer to support such a feature. Samsung has had a similar tool since One UI 3.1 that lets you turn certain Samsung Galaxy tablets into second displays for your PC — and there's a hidden feature that expands it to more tablets and even Samsung Galaxy smartphones.