I'm installing elementary OS.
It asked me for a product key and said there must be some Certificate of Authenticity on it, like this: 
I have tried visiting URL on this image, but it is replaced with some nonsense. Where is it located?
elementary OS does not use product keys or prompt for product keys.
Please ensure that what you have downloaded and are trying to install originates from the elementary website and that the checksum matches as per the installation guide.
