I've bought a game on Xbox One. The game is also available on Windows 10, but I want to know if it's possible to install the game I bought for Xbox One on my Windows 10 and play it for free ?
For this to work with a game, it needs to be part of Microsoft's Xbox Play Anywhere program. That link will take you to the program's official page, with a list of current and upcoming Play Anywhere games. Unfortunately, if the game isn't on that list then you will have to purchase it on your PC to play it there.