You've always been able to technically play Fallout Shelter on PC and Macs, thanks to the glory of Android emulators. But if you need another reason to dive into the vault, the game's officially available (for free, of course) on Windows 10 and Xbox One today.
If you want to quietly run Fallout Shelter in the background of your office PC, here's the Windows Store link. It'll run on a potato more or less, as long as that potato is powered by Windows 10.
For those on Xbox One, you can find the store listing here or through Xbox Live on the console. Both versions of the game fall under Xbox's Play Anywhere program, meaning your achievements and saves will carry over across platforms.