Most phones have the NFC function enabled by default. However, if you find that tapping the tag to your phone produces no effect whatsoever (no error message, nothing seems to be detected), then you may want to make sure that NFC is indeed enabled on your device.
On iPhone
On all recent iPhones, NFC is enabled automatically, and you do not need to toggle it on.
On Android phones
- Go to Settings
- Open "Connected devices"
- Tap on "Connection preferences" at the bottom of the list
- Tap on NFC
- Toggle "Use NFC" on.