Navigation Bar:
navigationController?.navigationBar.barTintColor = UIColor.green
Replace greenColor with whatever UIColor you want, you can use an RGB too if you prefer.
Navigation Bar Text:
navigationController?.navigationBar.titleTextAttributes = [.foregroundColor: UIColor.orange]
Replace orangeColor with whatever color you like.
Tab Bar:
tabBarController?.tabBar.barTintColor = UIColor.brown
Tab Bar Text:
tabBarController?.tabBar.tintColor = UIColor.yellow
On the last two, replace brownColor and yellowColor with the color of your choice.