To make sure people cannot find your cell phone number through the phone book or 411, you will want you number to be unlisted. You must call up your service provider to remove your number from the list. Some service provider can charge you a one-time fee for this service.
For those who wish their phone number to be blocked from someone’s caller ID, you can do this for each call you make. Consider pressing *67 followed by the phone number your wish to call. This technique works almost everywhere in the world.
For making your outgoing calls appear as private on a permanent basis, you must speak to the customer services representative from your service provider. There could be a one fee attached to this service. Once your network has activated the service, you can have your line blocked permanently by pressing *82 followed by the number.
If you want to make your number appear private to a certain phone number, you will be required to talk to your service provider and ask them if they can do it for you. If they do block your number, there is likely to be some kind of fee attached to their service.
For hiding your mobile number on iPhones, consider navigating to the main menu on your Apple iPhone. Find the Setting icon on the main menu. Tap that and look for an option called Settings. Tap it and a list of options will be displayed. Locate Show My Caller ID. If it is ON then choose Off to make your number appear private. Dial #31# for making your number private for a single call for most iPhones.