In Android 7.0, there are a number of expandable quick settings for things like WiFi and Bluetooth. Those toggles still exist in Android O, but the way you interact with them is quite different. Expanding requires you to tap the text instead of the icon.
The text in question if right under the icon—not the sort of thing that looks like a button you’d press. Tapping the icon toggles them on and off.
Android O feature spotlight: Expandable quick settings only work when tapping the text, not the icon was written by the awesome team at Android Police.