NFC support in mobile phones has come a long way since Nokia announced NFC in its Nokia 6131 NFC in 2007. Today, it is almost easier to ask which phone doesn’t support NFC in some way. So the short answer is: almost every smart phone supports NFC. A comprehensive — and frequently updated — list by NFC World can be found here.
But the relevant answer is not simply dividing all phones into a “yes” or “no” bucket. Depending on the application, you may need different NFC capabilities, as in, “phone as a credential” or “phone as a reader” and “phone as a writer”. (An additional mode is “peer-to-peer”, but it is less prominent at this point in time).
Most Android phones support all modes of NFC, that means you can use the phone as a credential (i.e., in payment applications with Google Pay), as well as using the phone as a reader (i.e., when interacting with the physical world in tags, smart posters, smart sensors, etc.) and using the phone as a writer (i.e., programming tags). This can be tried using an Android phone and Identiv’s NFC Tag Starter Kit.
Apple iPhones have gradually added more support for NFC, starting with an NFC chip in the iPhone 6 in 2014 and later models. In the beginning, Apple restricted NFC capabilities to principally one use case: using the phone as a credential to pay (i.e., Apple Pay). With the release of iOS 11 in 2017, the iPhone's NFC chip capabilities have been extended beyond Apple Pay, and now include reading tags’ NDEF messages. Just recently, with the release of iOS 13 in 2019, Apple has opened up NFC capabilities even further, allowing payment transactions with Apple Pay by simply tapping an NFC tag and without downloading specific apps. This means that product companies can expect more and more of their target customer audience to be able to interact with NFC-enabled products, be it for consumer engagement, receiving more information, or proving the product’s authenticity (i.e., anti-counterfeiting).