iPhone 6/6+/6s/6s+

Unfortunately although these devices have an NFC chip in them Apple have not made them available to work with NFC tags.

iPhone 7/7+/8/8+/X/

Apple introduced the ability for an iPhone 7 or 7+ to read NFC tags that are already formatted with data such as a URL.  Unfortunately this does not work natively on the phone so you have to use an application and once launched the app will be able to scan the data and launch the URL on a browser. There are plenty on the market but our sister company PROX IoT have one and it can be found on the Apple store here: PROX NFC Tag

iPhone Xs/XsMax/XR

With this model they freed up NFC reading so any NFC tags that have a URL written to them will launch the browser automatically without any need for an application.