When you make a call from your iPhone, either to a contact or a manually entered number, your phone number appears on the recipient's caller ID. This helps your friends and family identify you as the caller before they answer, and your number may also be reflected on their voicemails. Hiding your number on outgoing calls protects your privacy when you don't want the call recipient to have access to your contact information. Set your iPhone to hide your caller ID in a few easy steps.
Go to the "Settings" menu, accessible through the grey "Settings" icon on your phone's home screen.
Scroll down, and tap on "Phone."
Tap "Show My Caller ID." On the following screen, tap the "On" icon next to "Show My Caller ID" to toggle it into the "Off" setting.
Your caller ID will always appear when you initiate a FaceTime video call, even if you set your phone to hide your number.