** Here myTF is outlet for MT TEXT FIELD **
let border = CALayer()
let width = CGFloat(2.0)
border.borderColor = UIColor.darkGray.cgColor
border.frame = CGRect(x: 0, y: self.myTF.frame.size.height - width, width: self.myTF.frame.size.width, height: self.myTF.frame.size.height)
border.borderWidth = width
self.myTF.layer.addSublayer(border)
self.myTF.layer.masksToBounds = true