How do I connect a WiFi enabled wall switch?
The problem you have is that your current switch is wired as a switch loop. This means that a hot lead comes into the switch box and a switched hot lead leaves the box. There is no neutral wire in a true switch loop. Commonly a white wire is used for the line to the switch, but it is supposed to be marked with black tape or a marker to indicate it is hot.

While these are common in older circuits, current practice also requires a neutral wire to be present in most switches. And your new wifi switch needs a neutral. Unless there are other wires in the switch box, this switch cannot be used without additional new wiring.