Airplane mode works too, but that, obviously, shuts off cellular function as well. I just noticed that the Switch IS there on a Note 8, so it might still be there on the S7 Edge, but they'd have to follow the steps through the settings (Settings, Connections, Data Usage, Mobile Data switch). If they use a launcher that supports action shortcuts, they might be able to find the 'shortcut' to go to that screen directly.
If the concern is not using mobile data at all, what you can do is from the same Settings section, set up a mobile data limit to '0 MB'. That way, mobile data would be shut off automatically pretty much as soon as you set it up. And you can also set it to reset per billing cycle so that it does it every month.