Programmatically. There isn't a hide option. You have to set them even if you are 'hiding' one by not including it in the list. How depends on if you're using a UITabBar or a UITabBarController. Look for the set method in the appropriate class.
If you are asking how to change the name of the first view then that is another question. It can be done programmatically or via the tool bar on the right side "Attribute Inspector."