adduser has no difference from useradd

in fedora there is only useradd command, adduser is just a symlink to useradd.

you can check that with the following command:

ls -ld /usr/sbin/adduser

the output of the command:

[root@fedora28 ~]# ls -ld /usr/sbin/adduser
lrwxrwxrwx. 1 root root 7 Feb 6 05:37 /usr/sbin/adduser -> useradd