Bethesda have said all along that they plan to add mod support to Fallout 76 after launch, but it turns out the wait may be a lot longer than you’ve expected. Recent comments from Bethesda marketing man suggest it may be one while year before they add support for mods to their survival sandbox, which is a fair while. The game will need to have private servers before it’ll support mods, see, and (as also stated before) those won’t be in at launch either.
Source : rockpapershotgun.com