The "3 cs" is a popular guideline for writing user stories. what does each of the three c's represent?

The "3 cs" which is a popular guideline for writing user stories are;

First C is for Card

Second C is Conversation

and third C represents Confirmation.

Card contains the idea or little information and conversation contains the requirements and detailed description. Confirmation describes the acceptance and contains high level criteria.

If you follow these three c's, you can write an excellent user stories.