How to hide the number of Unicom card?

Need to open the calling hidden charging service, choose not to send the local number in the mobile phone menu (different mobile phone names will be different), or directly add #3 1# before the called number when dialing. Need to be reminded that this function only does not display the other party's phone number when the called party answers the phone, but the system will still record it, and the calling party's number can be obtained by querying the detailed list.