How to use NFC with RFID tags/chips
NFC tags are one type of RFID tags. NFC is a protocol for RFID, which can be understand by more and more devices.
You can buy NFC tags on amazon or other websites.

What can I do with that tags?
You can trigger something when you touch your phone to that tag. For example a NFC tag in your car which turns on Bluetooth, mutes your phone and turns off the lock screen. Then you can put the tag anywhere in your car and when you touch it your phone will be in your "car-mode"
However this requires some apps to work. For example 'Trigger' (https://play.google.com/store/apps/details?id=com.jwsoft.nfcactionlauncher) or 'NFC Tasks' are great apps for this purpose.