When you call someone through a Face Time call on an iPhone or iPad device, the person who receives your request can see the caller ID. It includes your Phone Number or Email ID that you are using with your device. If they save your contact, they know who you are, but they don’t have your number or address. They can find your contact details so you need to remember your caller ID correctly for that reason. Sometimes people do not answer the call if they can’t find the information about the caller. So if you wish to change your Face Time ID on your Apple Device iPad and iPhone, then this blog helps you to do this troubleshoot with easy steps.

Source :- https://elinajohn.wordpress.com/2020/02/15/how-to-change-facetime-caller-id-on-iphone-and-ipad/