How to get warranty on my recently purchase iPhone charger?

Your device and charger both automatically have a one-year limited warranty (AppleCare). If it breaks because of a manufacturing defect (and not normal use), Apple will replace it for you free of charge.

Has it a production flaw or a malfunction? If not, I wouldn't see any point of getting a warranty.

But if its broken or smith, grab your receipt, go to your nearest Apple store and tell them the problem regarding your charger.