Ark: Survival Evolved is a game that has been a widely successful game that has been optimised for multiple platforms over the last 3 years, Firstly coming to PC, Mac and Linux and then later to PS4 and Xbox One. The full official release of the game across all platforms is still expected to be spring 2017. Once this happens, there will be the option to purchase not only via a digital download but also to purchase a hard copy (disc) in store and online.
PC, Mac, Linux
Initially being released as part of an early access open beta stage for PC in June 2015 and then OS X (Mac) and Linux in July 2015. On these platforms it was and still is available for purchase via Steam. No hard disc copies are currently available for purchase on all platforms so steam keys are the only way to aquire this game. This can be down either through the steam website here or through the steam client on your laptop.
Ark: Survival Evolved came to console on December 6th 2016, but still technically in early access upon release for console, Ark: Survival Evolved can only be bought via the Playstation Store again either through the website here, through the PSN app on your phone or directly through the Playstaion Store app on your console. Any of these methods, if linked to your account, can be used to purchase and start the download of this game directly onto your console.
Again this was released for Xbox One on December 6th 2016. For this console the game can also be purchased via digital download from either the microsoft store website here, the xbox store site here, through online retailers as a digital code, or via the xbox live store on the console.