I have this NFC tag that I unlock a door with. Can I somehow copy the nfc tags info and store it on my phone and with a program or something use the phone instead of the tag to unlock the door? without the need of the tag.
Think about this. If it is this easy to do, and it does appear this easy, then anyone near you can copy your NFC tags. Some tags even have the address of the lock you want to control. Bad idea to have a lock controlled only by an NFC.
August Lock company has a lock that requires GPS, Bluetooth, and WiFi to act in concert to open a lock. And a lot of security experts rate it poorly secured.
If high security is required, encrypted NFC/RFID, in concert with a biometric component and a possible mechanical option (physical key or keypad entry sequence) is the way to go....and in a tamper-proof access point.
If, on the other hand, only casual convenience access is necessary (yard gate, garden shed), then simple NFC is fine.