If the mTAG is set to the fallback experience, all you need to do is tap/scan it and it will show you the ID. If you can't access the fallback experience, or if the tag is redirecting to a different URL, you'll need an app to scan the code. For NFC chips we recommend
NFC TagInfo by NXP; for QR codes we recommend
Decode IoT. The encoded URL on the chip or QR code should be in the format: https://mtag.io/n12345 (NFC) or https://mtag.io/q12345 (QR). Simply copy and paste the "12345" part of that URL and search for it in the mTAG table in the Dashboard.