How to extend apple care plus in india

It appears that you can only extend your AppleCare+ coverage in the countries listed in the following article.

Extend your AppleCare+ coverage - Apple Support (IN)

You can contact Apple Support and ask them for further information.

It looks like the ability to extend it is only in a few countries

Extend your AppleCare+ coverage - Apple Support

You will need to address this with Apple; they may not offer extensions in your region.