Phone numbers and phone number ranges to block can be added or removed from this screen.
Tap the plus sign button to add a phone number or a phone number range. (A pop-up will appear to let you choose which one you wish to add.)
Tap a phone number or a phone number range entry to edit it.
Slide a phone number or a phone number range entry from right to left to delete it. You may also tap the “Edit” button to turn on the standard iOS “delete” mode.
When changes are made, the app will process the rules (i.e., build the block list, then remove any block list entries that are in the allowed list) and refresh the call-blocking extension.