I can’t find any screenshot that would fit your description.
If that has the same meaning as for a regular OS install, it just wants you to create a user account and you just type in a user name you want to pick and a password that you pick yourself.
In most Linux installs I did I used the same password as root password (the user root equals about the administrator in Windows)
So, you basically want to auto-login to your user account when you start an openSUSE app from Windows through WSL?
I don’t think most users here have experience with that. You probably would have to ask that from a WSL forum.
To me it’s still unclear what you want to achieve. Is there a native openSUSE/Linux application that you need to run from Windows?