These cards will not be available to pull in packs. Instead, players of the Japanese-language Pokémon TCG will be tasked with filling out a form available through their official Player Club Accounts. This must be done from July 21st to September 30th. The form will request Pokémon TCG players to submit a report of a game they've played with family or friends, and that form will act as a ticket to a promo card lottery. Winners, it seems, will be given the set of three Alternate Art VMAX cards.
There is no current information as to whether or not these will be released internationally. For all we know, these could show up in the Evolving Skies set with the rest of the Eeveelutions. However, longtime Pokémon TCG source Pokébeach expressed some doubt about a future release, remarking:
It's possible we could get these cards in a future set. However, limited print runs are often kept exclusive to Japan.