It is possible to use your mobile device to scan a NFC tag, with the Native client.
If you are working with an external writers/scanner you should consult their documentation how to integrate this with your app.
Anything is possible, but some more information on the device you plan to use would be useful.
Some external RFID readers can behave as a keyboard HID, so when a tag is scanned it outputs the data as if someone has typed it in. There is no special code needed in this case.