https://www.gamespot.com/articles/e3-2018-fallout-76-is-an-always-online-multiplayer/1100-6459647/

We finally learned what kind of game Fallout 76 is. At the Bethesda E3 2018 briefing today, Fallout director Todd Howard confirmed that Fallout 76 is a multiplayer-focused, always-online game. The characters you come across in Fallout 76 are real people. The game is entirely online.

However, you can also play by yourself, Howard confirmed. "Of course you can play this solo," he said. Regarding why Bethesda is taking Fallout in such a new and different direction, Howard said, "We've always wanted to see what our style of game could be with multiplayer."