Apple Watch apple care
I want to get my Apple Watch included in my apple care plan
Apple Watch Series 3, watchOS 7
Question marked as
How long have you owned your Apple Watch? If longer than 60 days, you cannot add an AppleCare Plan. If less than 60 days, you don't add a watch to an existing plan, you buy a new plan for the watch.
See this link --> Buy an AppleCare plan - Apple Support