Can two people using two iPhones with the same ID make calls independently?

No, two people using iPhones with the same Apple ID cannot hear each other's phone calls. Each call is private to the device that is making or receiving the call. Sharing an Apple ID does allow for sharing of other data like contacts, photos, messages, and app purchases, but it does not provide any capability to listen in on each other's phone calls.

However, sharing an Apple ID can lead to some privacy issues as messages and other notifications can appear on both devices. It's usually recommended to have separate Apple IDs and use features like Family Sharing to share purchases, subscriptions, and other content while maintaining individual privacy.

narissa35 wrote:

Two people using two iphones with same id can they hear one calling a third person and talking? Can they hear the conversation?

[Re-Titled by Moderator]

Apple has for years recommended two people should NOT share the same Apple ID. Read this --> Make sure that each family member has a unique Apple ID - Apple Support

If you share an Apple ID with someone. They will see the calls each of you make. They will have access to all voicemail messages. They will be able to read each others text messages. And they can, if they get mad, change the Apple ID password, locking one out of their iPhone or even erase the phone remotely without your knowledge or permission. They'll be able to delete contacts or photos without either's permission. There are so many reasons why sharing an Apple ID is ill advised.

If none of that concerns either of you, it's up to you if you want to share an Apple ID with someone else.

narissa35 wrote:

Two people using two iphones with same id can they hear one calling a third person and talking? Can they hear the conversation?

The same Apple ID? If the caller calls their Apple ID email (such as FaceTime), all devices will get the call but only one will be able to answer it. If the caller calls the phone number connected to the SIM, then only the phone with that number gets and can receive the call. All devices connected to that Apple ID will be able to see the call in the call log though.

They cannot hear calls made from another device, but both devices will receive the same call logs and voicemails. If Messages in iCloud is turned on, they will also receive the same messages.

A single Apple ID should NOT be shared by multiple people. Each person needs their own Apple ID.