By default, from how I understand it, the root account is login-disabled and so it doesn't *have* a password. All methods involving invoking the root user that I know of (link) start by establishing a password for it. Why do you *need* the root user?
I know how to change it, I'm asking if it is ok to do so. Like do any of the apps or iTunes use this password?
Wrong. We're talking iPhone Mac OS X here, not Mac OS X for Macs ... The root user is used standard, mobile is not used. When you turn your iPhone on, you are logged in as root. The root password is dottie. To change it, install MobileTerminal and BSD Subsystem, then execute this in the terminal:
passwd root
Then it will ask you to type the new password twice, and you'll have changed the password.