What are the key points of article 5 of the constitution?
Article V of US constitution deals with the procedure of introducing amendments in US constitution. It entails that both houses of US Congress must pass the said amendment with a two third majority after which the amendment is sent to states for ratification.
The word ratify means "to pass, or approve". So, you're essentially asking which article of the constitution tells us how to approve the constitution and make it law. I think what you mean is "What article tells us how to amend the constitution." To amend the constitution means to somehow change it, which has only happened 27 times. Article #5 tells us how to amend the constitution.