The digital version of Wizards of the Coast's Magic: The Gathering, Magic: The Gathering Arena, has now launched out of beta.
The game, which launched Sept. 27, 2018, in closed (then open) beta, is now available as a fully-fledged computer game.
Magic: The Gathering Arena, also simply known as Magic Arena, is available exclusively for Windows until a MacOS version comes out in 2020. WotC has not yet announced any plans for versions of the game for iOS or Android.
Magic Arena is a free-to-play "freemium" game with a heavy lean towards eSports.
You can download Magic Arena from the WotC website.