NFC stands for “Near Field Communication” and is available in most smartphones.
The concept is that you can place your phone close to another device (typically within 4″) and can share/send information just from being close to it.
Apple has recently started using NFC with their highly touted “Apple Pay” in which you put your phone close to a receivable Credit Card machine and the App takes care of the rest.
Android has been using NFC for a while in multiple ways including their similar pay-app, previously called “Google Wallet” and now renamed to Android Pay, so that people are less confused with the names.
Another cool feature on Android is “Android Beam” which lets you put your phone next to another Android device and share any file/data you’d like. This could be links, maps, apps, or even music/video files.
On my phone (a Moto X (2nd Gen.)) I keep “NFC”, “WiFi” and “Bluetooth” on and in use all day long, and don’t see much of a difference in battery life, from when they are off. Not only are they on, but most of them are in use throughout the day, with WiFi connecting both at work and at home, and my Bluetooth in constant talk to my watch.