id Software has officially announced mod support for Doom Eternal. You can try out the modding tool for free on Steam.
We are so impressed with the Doom Eternal community mods created without any official tools. They inspired us to release a public beta of idStudio for creators and an opt-in PC Mod Preview for players to easily browse and play mods.
The Doom Eternal: idStudio toolkit is currently in beta, but anyone on a PC can download and use it. You can download it here. To install custom mods created with this program, go to the game's properties in Steam and select the «Betas» tab and «pc-mod-preview». This will allow you to download mods. More detailed instructions can be found on the id Software website.
By the way, new interesting details about the upcoming Doom: The Dark Ages have appeared. And also improved versions of the first two parts of the cult shooter series have been released.