Linux add a user to group with adduser
adduser command like useradd, used to add a user to linux server.
adduser is more interactive, while useradd require all options passed using command line options.
adduser [options] [--home DIR] [--shell SHELL] [--no-create-home] [--uid ID] [--firstuid ID] [--lastuid ID] [--ingroup GROUP | --gid ID] [--disabled-password] [--disabled-login] [--gecos GECOS] [--add_extra_groups] user
For creating system user, run
adduser --system [options] [--home DIR] [--shell SHELL] [--no-create-home] [--uid ID] [--group | --ingroup GROUP | --gid ID] [--disabled-password] [--disabled-login] [--gecos GECOS] user
To add a user, run
useradd USERNAME_HERE
To delete a user, run
deladd USERNAME_HERE