How to block your number on your UNA iPhone
Select the “settings” icon on your iPhone, and go to ‘Phone’.
Scroll down to “Show My Caller ID” and select. If you are currently allowing your number to be seen, the button will be highlighted in green. Hit the button once to toggle to off.
When you make calls, your number will show up as “Blocked” to the person you’re calling. Even if your friends have your number saved in their address books, the number will still come up as “blocked” and they will not be able to tell that it is your phone number.
To switch back to normal mode. Go through the process as above for “Show My Caller ID” and toggle to “on” by tapping the toggle once.