@Homeguy 

Tapo care are avaible in both the U.S. and Canada so you can subscribe the tapo care in those areas. 

https://www.tapo.com/ca/tapocare/

https://www.tapo.com/us/tapocare/

' if i get the c210 from the United States can i register it here and still be able to use the tapo care? '

Yes, as whether Tapo care is available is based on the region of your TP-link account , the region is selected and fixed when you created a tp-link account

But if you purchase the products from a different country, kindly note that TP-Link does not provide international warranty service. Your TP-Link product is only covered by the warranty policy of the country where the product was originally purchased. Here is the RMA policy details for reference.