CODE EXAMPLE FOR DART

How to Change the underline Color of TextFormField

TextField(
 decoration: InputDecoration(
    enabledBorder: UnderlineInputBorder(borderSide: BorderSide(color: Colors.red,width: 2.0)),
    focusedBorder: UnderlineInputBorder(borderSide: BorderSide(color: Colors.teal,width: 5.0)),
    labelText: 'Your Email or Phone'
  )
)