Glossary
NFC
NFC is a 13.56 MHz contactless technology for exchanging data over a few centimetres: payments, access badges, transit cards.
NFC (Near Field Communication) is a contactless communication technology working at 13.56 MHz, over just a few centimetres. It powers contactless payment, many access badges and transit cards.
An NFC tag has no battery: the reader's field powers it. Most phones can read common tags (NTAG, for example); older families such as MIFARE Classic need a dedicated reader like the Proxmark3.
NFC is a branch of RFID. To experiment on your own tags, blank NFC cards are all you need.