How to add new user in Arch Linux use useradd command
useradd -m -g [initial_group] -G [additional_groups] -s [login_shell] [username]
useradd - create a new user or update default new user information
[initial_group] mean default group
[additional_groups] addition group, remember that a user can follow more than one group.
Now test
Normal user
sudo useradd username
Admin user
useradd -m -g users -G wheel
Make normal user become Admin user
usermod -aG wheel username
Test,
Ok,
For Debian/Ubuntu base replace wheel by sudo for admin groups.
Read more at [Users and groups](https://wiki.archlinux.org/index.php/...)