This allows you to play certain games on both Windows 10 PC and Xbox One with a single purchase. Microsoft has confirmed it will be live from September 13.
"The Windows 10 Anniversary Update and the related Xbox update coming this summer enable the Windows Store on Windows 10 and Xbox One to support Xbox Play Anywhere games," a Microsoft spokesperson explained to Polygon. "Then, beginning with the launch of ReCore which launches on September 13 this fall and continuing with Forza Horizon 3, Gears of War 4, Halo Wars 2 and others, when you digitally purchase a game that supports Xbox Play Anywhere, you have access to the game on both Xbox One and Windows 10 PCs for one price and your progress, game saves and achievements are shared seamlessly across both platforms."
What this means is, you will be able to play the same game on Windows 10 PC or Xbox One, wherein your save progress carries over along with a single list of achievements, and downloadable content (DLC) bought on either Windows 10 PC or Xbox One will work on both.
Keep in mind that this is only valid on digital download versions of games, not those on disc. You will also need the Windows 10 Anniversary Edition update on your PC slated for August 2 and the summer update for the Xbox One.
As for games that support Play Anywhere, they will be listed on the official Xbox site as such and will sport a Play Anywhere icon in the online store.
For now though, the confirmed list of titles with Play Anywhere include the aforementioned ReCore,Gears of War 4,Forza Horizon 3, and Halo Wars 2. Others areScalebound, State of Decay 2, We Happy Few, Crackdown 3, Killer Instinct Season 3,Ark: Survival Evolved,Cuphead, We Happy Few, and Crackdown 3.