I have the apple care for my iphone 12 can I transfer that care when i purchase my iphone 13

No. AppleCare stays with a device for its duration.

If you wish, you may cancel the AppleCare when it no longer applies to your iPhone 12 and purchase a new AppleCare plan for your new iPhone.

AppleCare may be transferred - as described in the linked article above - to a new device owner.