Apple’s iPhone 7 and newer with iOS 11 can read almost all types of NFC tags that are NDEF encoded with certain requirements.
Buy Encoded NFC Tags
When buying NFC tags, make sure to purchase them with encoding and/or have an alternate way to encode the NFC tags. The GoToTags Store can encode NFC tags for customers. The NFC chips must be NDEF encoded; a better option is Platform encoding (also NDEF) which allows the tag owner to remotely change the action of the tag and gather interaction analytics.
Encode NFC Tags
To encode NFC tags yourself; purchase an NFC reader/writer and use the GoToTags NFC Encoder software. For small quantities, an Android phone can also be used.
NFC Tags on Amazon
Most of the NFC tags sold on Amazon are not pre-NDEF encoded and will not be able to be read by an iPhone until they have been encoded. Read more about NFC tags on Amazon.