I'm new to this famous card game. I searched it on steam and found multiple version e.g. 2012, 2015, etc I'm planing on purchasing this online version of the game to see it but I got curious. Does the game has a new version as an entire new game every year? If so do I have to purchase the 2016 version next year to stay up to date? Thanks
You appear to be talking about Duel of the Planeswalkers, a game based on M:TG where you start with a number of decks and you unlock cards to add to those as you progress in the game. There were different versions for the past few years. Each version had new decks and features. You can compare it to several sport games (NBA 2k15, WWE 2k15), they all get newer and sometimes better versions each year.
You can, however, keep using the older versions. But newer versions contain newer (and sometimes more) cards, new enemies, new battle types etc.
There is also Magic: Online, a true digital equivalent of Magic: The Gathering. This is a version which stays up to date with newer cards, but can be more expensive than the DotP versions you can buy (eg) in Steam. In MTGO, you create your own collection and play against other players, not against AI opponents.
Magic Duels is a free-to-play game that serves as an excellent tutorial and is now being updated with all new cards (but no old ones) rather than the yearly releases of the past.
WotC has now changed from a yearly release (DotP13, 14, 15, etc) to one release that will be supported going forward. This is called Magic Duels.
It came out with the Origins release, with the intention of providing running updates with each new set.
It is free to play; you buy booster packs with coins earned through victory, quests, or purchasing them for cash. Currently there is a starter pack provided when you download it that contains cards mainly from Origins, but there are also some cards from throughout Magic's history. There is also a Battle for Zendikar starter box, and likely to be a starter box for each large set.
Other than that, all cards in the app are from Origins and Battle for Zendikar. Oath of the Gatewatch was not able to be provided in time and is being added Wednesday, April 6, at the same time Shadows Over Innistrad is added to the app.
The game serves as an excellent tutorial as it explains each mechanic as you come across it through guided scenarios, but they are optional so if you already know what you're doing you can move on. The app also contains stories based on the Magic Storyline that closely (though not precisely) follow the stories of each planeswalker for the Origins set, and an additional chapter for Battle for Zendikar.