Differences between the three Ask to Join Networks settings in iOS 13? Before the release of iOS 13, when navigating to Settings/Wi-Fi/Ask to Join Networks there were two options listed: On/Off. The idea was that if this setting was enabled, if the iOS device in question was out-of-range of any known Wi-Fi networks but there were networks in range that hadn't yet been connected to, the OS would pop up a notification giving the user the option of joining these networks - some users may have found this useful if they travel a lot, for example.

In iOS 13, however, this simple switch has been replaced with three options: "Off" (which I assume behaves the same as it did in previous iOS builds), "Notify" and "Ask". To me, at least, these latter options sound similar and the tooltip displayed when either of these are enabled isn't too helpful.

Would somebody be able to explain the differences between these two latter settings?
What I commented above was almost correct.

the popover was very annoying to see when Wi-Fi is on and I am away from known networks. So maybe a notification comes when there's none. So that I can finish what I was doing and then try to connect to something.

The excerpt from an article:

Off ( This requires you t manually select a network if no known
networks are available)
Notify ( Known networks are joined
automatically. If no known networks are available you will see a
notification for available networks)
Ask ( Known networks are joined
automatically. if no known networks are available you will be ‘asked’
before joining a new network.

From https://appletoolbox.com/wi-fi-issues-after-updating-to-ios-13-or-ipados-check-these-10-tips/
The difference seems to be in the direct popup with list of networks vs the notification about available networks which won't interrupt your work.