An nfc tag has an nfc chip inside of it which performs the nfc interactions. There are several nfc chip types available and the choice of which nfc chip type to use is important. Each nfc chip has its own characteristics, features and cost. The nxp ntag series is typically what customers use. The nxp ntag series comes in a variety of data capacity sizes and they offer the best device compatibility.

Nfc tag technical specifications
Frequency: 13.56 mhz
Protocol: iso14443a
Thickness: 0.3mm without anti metal layer, 0.7mm~1.0mm with anti metal layer
Antenna: al etching antenna
Material: paper, pvc, pet, etc
Finish: glossy, matt
Printing option: offset printing, silkscreen printing, laser
Read distance: iso14443a: 2-5cm
Applications: cashless point of sale, mobile phones, turnstiles, vender, loyalty system for promotion, parking meters, e-payment, etc.