According to the FAQ published on the Fallout 76 website, both the beta (or B.E.T.A., as Bethesda dubs it) and the final version of Fallout 76 will be coming to Xbox One, Playstation 4 and on PC exclusively via Bethesda.net.
While this is not a big issue, it means that you'll need an extra launcher installed if you are going to play Fallout 76, and those are not in short supply these days.
Bethesda also confirmed that the beta version, which is slated to start in October, will include the full version of the game and progress made by players can be used in the final version when it launches on November 14th.
In case you are looking to be a part of the B.E.T.A. phase, all you need to do is pre-order the game, and you’ll get invited.