How to disable touchpad on modern dell laptop?

Hello. I have two Dell Vostro laptop series - the old (though it is still quite brisk) 5470 and the new 5468. In 5470 there is a remarkable functionality is - disable tochpad when the mouse is connected. In 5468 I did not find such a function. Maybe you tell me how to enable this feature or how to disable the touchpad quite Windows 10?