I’ve got an Android app called NFC Tools developed by Wakdev. Which allows me to read or write to NFC tags.
You can buy blank NFC tags for not a lot of money and program them with whatever data you want.
There is an accompanying app called NFC Tasks that allows you to perform preset tasks when any particular tag is read.
I haven’t really found a genuine use for it, mostly just gimmicky.
eg You can program a tag to be called “Work” and place it at your desk at work. Then when I get to work I place my phone on the tag and the phone automatically changes to silent mode and displays the calendar to show my meetings.