While Avowed has been compared to Skyrim, its gameplay is more akin to Obsidian's The Outer Worlds, a single-player experience. This begs the question: Does Avowed offer multiplayer capabilities? The short answer is no.
Avowed lacks both co-op and PvP modes. Your companions will be non-player characters (NPCs), similar to The Outer Worlds. Enemy encounters are solely controlled by the game's AI; there are no player invasions or any other form of multiplayer interaction. While initial plans included multiplayer functionality, Obsidian Entertainment ultimately removed it, citing a focus on other aspects of development. This decision, though initially marketed to attract investors, doesn't significantly detract from the core single-player experience.
Currently, no Avowed co-op mods are publicly known. While future modding possibilities exist, the complexity of such an undertaking is considerable. Furthermore, Obsidian has confirmed no plans to add multiplayer post-launch.
Therefore, Avowed is a strictly solo adventure.