There are two methods to add users to WSL distro (Windows Subsystem for Linux) - When logged in as a SUDO user and When logged in as ROOT.

Windows Subsystem for Linux is useful for developers who use Windows. Learn how to set default user, switch user & remove a user in WSL.

Microsoft has open-sourced the Windows Subsystem for Linux (WSL), making its source code available on GitHub, except for a few components that are part of Windows.