How can I (properly) hide my iPhone number when making calls?

Apple doesn't have much to do with it. They just pass on your request to hide Caller ID to your carrier. And it's just that: a request. Caller ID is a residential service, and that request specifically blocks Caller ID if it is honored.

Businesses (not just service providers) use an entirely different service called Automatic Number Identification (ANI). Blocking Caller ID does not block ANI. There is no way from a standard residential or cellular phone to block ANI.

I've always put *67 before typing out the phone number. If there are certain numbers that you always want to have blocked, save the contact with *67 in front of it so when you touch on the contact name, it'll block the number.

Hiding Caller ID for the most part only works when calling residential or cellular numbers. Almost any business can see your phone number, especially if that business has a toll-free number. Nothing you can do will prevent that. And this is not specific to iPhones. All businesses, except the very smallest ones, can always see the phone number that is calling them.

The only target phones for which Caller ID will go through despite prepending *67 to the phone number are calls to toll free telephone numbers. The reason for this is that toll free numbers are not free at all -- they are automated collect calls and the party paying for the call is entitled to know who is causing him to pay for the call.

Re: “… But I didn't know that it still worked in this day and age … “

LOL

Because of it’s sheer enormity and inherent requirement for near-perfect interoperability … the underlying PSTN methods for call setup and switching evolve at a sub-glacial pace.

Plus … those engineers at the “old” AT&T and Western Electric were REALLY, REALLY good at figuring out HOW to do it !!!

Hello. I’m sorry. But why would you need to hide your identity? Just curious. Thank you