While Fallout 76 doesn’t have any human NPCs to engage with, it is possible to join a number of factions in the game, ranging from cultists to the Enclave. While previous Fallout games have let you align with different groups to conclude the game’s main quest and even form alliances for side quests, factions in Fallout 76 are all about players unlocking access to bespoke gear.
Fallout 76 factions are very different from the way factions have been handled in previous Fallout games, nominally because there are no human NPCs in Appalachia for you to receive quests from in the first place.