I got the apple watch care but lost the reciet what happens

Hi Joey

AppleCare+ is registered automatically and is recorded against your Apple Watch, so you won't need your receipt.

You can check your coverage here by entering your watch serial number (you can find this on the back of the watch):

https://selfsolve.apple.com/agreementWarrantyDynamic.do

Or by viewing your watch within your Apple Support Profile here:

https://supportprofile.apple.com/