can apple care + be transferred to new device

Not that I know of. You will most likely need to cancel it separately. You can, however, cancel it (if within the first 30 days you will get a full refund of the Applecare) and then purchase another with the new phone.

Just to be sure, do ask Apple - we are just other users here. Here are the terms for Applecare+:

https://support.apple.com/en-us/HT202704

https://www.apple.com/legal/sales-support/applecare/applecareplus/docs/applecareplusnaen.html

As mentioned, AppleCare+ is tied to the device. Once you return the phone, you cancel the AppleCare+ Plan and buy the new phone and a new AppleCare+ plan. I wrote a user tip about AppleCare+ which you might find helpful. Click this link --> Demystifying AppleCare Plus / AppleCare P… - Apple Community

If you are within the 14 day return window you can return the device and the AppleCare + for a refund then buy the new iPhone and AppleCare + again. It is tied to the device.