Dialing an extension
When you need to call an office, university, or government building, you’ll need to input an extension in order to reach the correct person. To do so on your iPhone isn’t all that well-known, but it’s possible. In fact, it takes very few taps on your phone screen to get it done.
After opening Phone and typing in the number, press and hold the * button and wait until you see a comma appear on screen. Next, input the extension number after the new comma, and you’re all set. This handy feature will help you call someone at a large building directly while avoiding bugging people you don’t need or want to communicate with.