Aditya, it seems your dog is from 'unknown pedigree'. It's quite difficult to get such dogs affiliated to KCI. However, you can get the registration form downloaded from KCI website. You need to get an appointment from a KCI judge and need to take the dog along with his photos. If the Judge is happy with the breed standards of your Labrador, he will authenticate the form which you then need to send to the KCI headquarter in Chennai. The papers may take time to come . These days dogs are also micro-chipped which makes the identification process easy during dog shows.
If you fail to get the appointment from the Judge, you may wait for the dog show in your city next season. You can take the dog along in the show and meet the Judge directly.