Steam Remote Play Together is a feature on Steam that lets you play local co-op games online. Something like Parsec, but available straight from Steam.
The way it works is that it’s an extension of the Remote Play tech. Instead of streaming the game running on your PC natively to a device in your home, it can now stream to your friends’ device.
The feature is now available for everyone. Even folks without a Steam account can now join in as guests by sharing a URL link. Though they do need to use the Steam Link app to see the stream.
You can find the games in your library that already supports Remote Play Together by clicking this link (it will open your Steam client and adds a Dynamic Collection in your library).
In addition, Steam will be holding a Remote Play Together Sale and stream beginning March 25.
With most folks in the world currently can’t meet close together due to the pandemic, Steam Remote Play Together is a handy way to play games together, without having everyone buy their own copy. Only the host has to own the game. With this update, you don’t even have a Steam account either.
Source: Steam