how to make custom TextField in flutter.

MyApp.dart

Widget getCustomTextField(
      TextEditingController _controller, String hintText) {
    return Container(
      height: 65,
      child: Padding(
        padding: EdgeInsets.only(top: 8, bottom: 8),
        child: TextFormField(
          controller: _controller,
          decoration: InputDecoration(
            isDense: true,
            fillColor: Colors.grey,
            filled: true,
            focusedBorder: OutlineInputBorder(
              borderRadius: BorderRadius.all(Radius.circular(10)),
              borderSide: BorderSide(color: Colors.grey, width: 1),
            ),
            enabledBorder: OutlineInputBorder(
              borderRadius: BorderRadius.all(Radius.circular(10)),
              borderSide: BorderSide(color: Colors.grey, width: 1),
            ),
            border: OutlineInputBorder(
              borderRadius: BorderRadius.all(Radius.circular(10)),
              borderSide: BorderSide(color: Colors.grey, width: 1),
            ),
            disabledBorder: OutlineInputBorder(
              borderRadius: BorderRadius.all(Radius.circular(10)),
              borderSide: BorderSide(color: Colors.grey, width: 1),
            ),
            suffixIcon: Image.asset(
              Icons.help,
              color: Colors.blue,
              height: 10,
              width: 10,
            ),
            hintText: hintText,
            hintStyle: TextStyle(
             fontSize: getFontSize(16),
             color: hintColor,
             letterSpacing: 0.22,
           ),
          ),
        ),
      ),
    );
  }