According to the company, starting in early April, users of the Bethesda.net launcher will be able to transfer games and wallets to their Steam accounts. Users who own the game through the Bethesda.net Launcher will not lose data from their Bethesda.net account. Game progress and game save files will also be migrated, but users will need to manually migrate certain games. For games that require manual movement, users still use their old Bethesda.net account information to log into the game. The Bethesda.net account will not disappear and will remain accessible on the website and in-game. Bethesda will share detailed migration instructions in April.
Through May, users can still access and play on Launcher Bethesda.net, but the publisher advises that the “move” should take place as soon as the migration officially begins. Users will not lose access to the Bethesda.net gallery in May, but will not be able to play on this launcher.
Additionally, when transferring your library from Bethesda.net to a Steam account, all virtual currency balances and add-ons such as DLC or in-game skins will be automatically migrated. Games with the friends list on Bethesda.net will be merged after the move (including Fallout 76, Doom Eternal, Wolfenstein: Youngblood, The Elder Scrolls: Legends, Rage 2, and Deathloop).
Readers can learn more about this topic. here. Bethesda also posted a Fallout 76-specific FAQ. here.