Can my warranty be extended

If you’ve purchased AppleCare+ when you purchased the device or within 60 days, the AppleCare+ coverage can be extended:

Extend your AppleCare+ coverage - Apple Support

If you didn’t purchase AppleCare+ within 60 days of purchase, AppleCare+ is not available for purchase.

Abhishekreddysripathi wrote:

I did not purchase AppleCare+ in purchase of 60 days

Can I purchase it now

No. If you didn’t purchase AppleCare+ within 60 days of purchase, AppleCare+ is not available for purchase.