The Fallout 4 mod support that Bethesda Game Studios has promised for consoles as well as PC should arrive sometime this spring, director Todd Howard told Game Informer.
Mods, of course, already exist for the PC edition; what Howard is referencing here is the Creation Kit, the free toolset based on the same utilities Bethesda used to make the games. The kit facilitates the sharing of the mods. That's how they'll be available for the Xbox One and PlayStation 4 editions of the game.
Howard said Bethesda is aiming to release the Creation Kit for PC between the first two DLC add-ons, which are coming in March and April. The Xbox One will get the Kit a month or so later, Howard said, and then the PlayStation 4 will get it a month after that. So this figures to be an April-May-June rollout.
Already a heavily customizable game, what with the features available for crafting and building settlements, Fallout 4 has already seen plenty of unofficial modding on PC, ranging from the ridiculous to the sublime.