Apple does not offer or support all features and services in all countries. It looks like currently Bhutan is not supported for two step verification and maybe iMessage. There are even countries where Apple does not do business at all.
There is nothing any fellow user here can do about that. It is up to Apple to decide what they support and where.
For FaceTime, you need to be using a supported carrier, and the only supported carrier in Bhutan is B-mobile (Wireless carrier support and features for iPhone in Asia-Pacific - Apple Support).