To change your password, all you need to do is run the passwd command, and provide your current and new passwords.
[nikdoof@s1 ~]$ passwd Changing password for user nikdoof. Current password: New password: Retype new password: passwd: all authentication tokens updated successfully. [nikdoof@s1 ~]$
By default, every new account is set to use bash as the login shell, but this can be quickly changed using the chsh command. Passing the argument --list-shells will show you all the shells you can switch to on the system.
[nikdoof@s1 ~]$ chsh --list-shells /bin/sh /bin/bash /usr/bin/sh /usr/bin/bash /usr/bin/tmux /bin/tmux /usr/bin/zsh /bin/zsh /bin/csh /bin/tcsh /usr/bin/csh /usr/bin/tcsh
Once you've decided on a shell, you can run chsh without arguments to switch to the new one, to confirm you'll need to provide your password.
[nikdoof@s1 ~]$ chsh Changing shell for nikdoof. New shell [/bin/bash] /bin/zsh Password: Shell changed. [nikdoof@s1 ~]$