Normally, when you place a call from your iPhone the recipient can see your phone number -- provided his phone has caller ID capabilities. If you want to hide your identity when you make calls, disable the caller ID on your iPhone. Once caller ID is turned off, your phone number will appear as private or blocked on a recipient's phone. If you have an iPhone model with FaceTime video calling, know that your identity will always appear to your call recipient, even if you disable caller ID.
Click on the "Settings" icon on your phone's home screen.
Scroll down to the third section of the page and tap "Phone."
Tap on "Show My Caller ID" in the "Caller" section.
Tap the "On" icon next to "Show My Caller ID" to toggle the icon into the "Off" position.