iPhone Handoff allows users to share a single phone number between multiple iPhones. This feature is configured within the Settings app under the Cellular menu. During setup, one iPhone is designated as the main device, and another as the companion device. The main iPhone retains the primary eSIM, while the companion iPhone receives a secondary eSIM for the same number. This setup enables seamless switching between devices using the identical phone number. All cellular settings are managed from the main iPhone. Location sharing is determined by the iPhone currently utilizing the phone number. This functionality is particularly beneficial for users with multiple iPhones, such as developers or reviewers. A significant requirement for this feature is carrier support. The hope is for widespread adoption by carriers, similar to their support for cellular Apple Watches.