When you make an outgoing call on your iPhone, the recipient sees your phone number by default, so if you want to make phone calls on your device while protecting your privacy, turn off the caller ID feature. With this feature turned off, people you call cannot view the phone number attached to your iPhone. The identity of incoming callers still shows up on your screen, unless they have also blocked caller ID.
Click on the gray Settings icon on your iPhone's home screen.
Scroll down to the third section of the screen and tap "Phone."
Tap the "Show My Caller ID" line.
Tap the "On" button next to "Show My Caller ID" to toggle the button to the "Off" position.
If you make a video call using an iPhone with Face Time capabilities, your number appears in the recipient's caller ID, even if you turn the setting off.