You can block your number from appearing on the caller ID of the person you are calling by entering a simple code. You can initiate a temporary block, or you can choose to make the blocking of your phone number permanent. The choice is yours but the methods are different. There may be a fee associated with this service. It can be performed on both land lines and cell phones.
Decide if you want the block to be permanent or if you want the ability to have your number show to some people all the time. There are codes that you can enter that will make your number not visible on Caller ID as long as you remember to enter it before you make the call. If you think you won't remember, then perhaps the permanent solution is a better choice for you. You can always show your phone number for a particular call by dialing *82.
Call your phone company and tell them you want your number blocked from caller ID. Specify that you want this effective for all outgoing calls. They will change their system to not identify the number the call is coming from to the party being called. There may be a charge for this service. Some phone systems don't charge but it varies from phone system to phone system.
Dial *67 and then the number you want to call and your phone number won't show up on the caller ID at the other end of the call. This will not work if the number called is a toll-free number such as 700, 800, 900 area codes. Any emergency services call will also show the phone number the call is originating from.
Use this same code, 67, before the number you are calling on your cell phone to block your cell phone number from being sent with caller ID, and if you want your blocked number to be visible, then dial 82 before the number you are calling.
Always inquire from your phone company or cellular provider if there are charges for these services. You don't want to receive a nasty surprise on your next phone bill.