iOS - Getting desired shadow above UITabBar

Swift 4:

tabBar.layer.shadowOffset = CGSize(width: 0, height: 0)
tabBar.layer.shadowRadius = 2
tabBar.layer.shadowColor = UIColor.black.cgColor
tabBar.layer.shadowOpacity = 0.3

You can give shadow by using following code to any UI object

tabBar.layer.shadowOffset = CGSize(width: 0, height: 0)
tabBar.layer.shadowRadius = 2
tabBar.layer.shadowColor = UIColor.black.cgColor
tabBar.layer.shadowOpacity = 0.3

Here i gave example for your tabControl object.

For Swift 5 :

tabBar.layer.shadowOffset = CGSize(width: 0, height: 0)
tabBar.layer.shadowRadius = 2
tabBar.layer.shadowColor = UIColor.black.cgColor
tabBar.layer.shadowOpacity = 0.3