Sidecar in macOS turns your iPad into a second display, but it's limited to certain Macs and iPads. Thankfully, a few third-party apps can help if you have an older Apple device or Windows PC.

spacedesk is a free app that lets you use an Android tablet as a second display for your Windows PC. Learn how to set up and use it.

The Galaxy Tab S11 series upgrades Samsung DeX with the ability to use the tablet screen as a second DeX monitor, giving ...