I have upgraded my phone can i transfer apple care or so i just stop direct debit

You cannot transfer Apple Care from one phone to another. However you can either cancel it or transfer it to a new owner of the old phone. See: Cancel or change the payment method for your AppleCare plan - Apple Support or

Transfer your AppleCare plan - Apple Support

I just called Apple Support regarding this same question, as I am thinking about upgrading from the iPhone 12 Pro Max to the 14 Pro Max. The person I spoke with told me I can transfer my current AppleCare plan to my new phone, but I would have call them as soon as I activate my new phone to get that transferred. I would recommend calling Apple Support (got to them through the Apple Support app) right away to get your plan transferred. Hope this helps!