Hide Your iPhone Number For Calls
When you call somebody from your iPhone, you are sending your phone number automatically. So your contact person knows right away the name of the caller in case the person saved your phone number as a contact. This can be practical, but maybe you want to hide your phone number once in a while. On your iPhone you have two ways to call somebody anonymously. You can either hide your iPhone number for all outgoing phone calls or only for single ones.
Hide iPhone number for all calls
One of the methods could be to hide your iPhone number generally, means for every single call you make from your iPhone.
If you want to do this, go to your Settings. Scroll down to Phone and click it. On this screen you see under Calls the option Show My Caller ID. Click it and then deactivate this feature by tapping the green button.
Hide iPhone number only for one call
The second method is for individual calls. You can hide your iPhone number by utilizing a GSM code, which you enter in addition to the normal phone number.
Open the Phone app and choose the Keypad in the bottom bar. Before you enter the phone number, you type the code #31# and then the phone number. Once you have entered everything, you can hit the call button as usual and your call will be anonymous. All other calls you make without the #31# pre-code will still send your iPhone number.
It also works the other way around. If you have deactivated to show your caller ID (as described above), you can show it for one call. Then you have to use the GSM code *31# though.