Can you use Apple Care+ without any checks (bringing just MacBook)? My MacBook Pro 15-inch 2017 is purchased in USA by a friend of mine.

I think there is hardware issue because sometimes screen becomes black and I have to restart it.

I have checked coverage by serial number at checkcoverage.apple.com and it says MacBook is covered by Apple Care Plus. 

I don't have any papers like a check but I have original box.

I am going to USA soon. So my question is: Can I have a service from Apple by bringing them only MacBook without any papers?
Yes, they confirm AppleCare status in their system, and you don’t need to provide anything else. 

At least, that has been my experience.