Marry’s iPhone), you can easily determine if you signed into a new device or that was someone else. Since the prompt shows the name of the device (e.g. Sometimes Apple ID gets stuck updating so there’s nothing new there. It might take some time for Apple servers to update new information and send it to your main device. If you don’t see it immediately as you sign in, worry not. If you get the “Your Apple ID and phone number are now being used for iMessage on a new iPhone”, it usually means that you added your Apple ID on a new iPhone.
