factime

Hardware-wise, the phone supports it.

However, in some countries (notably Middle Eastern) it is banned, either by the carrier or by local laws.

Apple provide a support document that shows which features are supported in which countries, by which carriers:

Wireless carrier support and features for iPhone in the United States and Canada - Apple Support

It works in Tenerife - Spain?

the phone has a front-facing camera (as have all iPhones since the iPhone 4 IIRC), so it supports FaceTime ss long as your carrier does.