Before I can give you links of program which you need to flash tell me the model number of your PHONE Settings->About device. It will be something like “SM-N910F” . After you share that I will give you the firmware version you need to download so you do not mess up , also when you say you want to unroot I am assuming that you want to go back to STOCK (the way your mobile phone should be when its brand new)
The Files You Need
Unrooting the Samsung Galaxy Note 4 (Verizon)
1. Right-click on both Odin and Stock Firmware and select Extract here. It’ll extract files from both of these archives to your desktop.
2. Double-click on Odin executable and it should launch.
3. Click on PDA and choose Stock Firmware available on your desktop. It’s the firmware file that you extracted from the archive and not the archive itself.
4. Uncheck Repartition if it’s already checked in the Odin.
5. You can checkmark the boxes that say Auto Reboot and F. Reset Time.
6. Turn OFF your device.
7. Reboot your device into download mode by holding down Volume DOWN, Home, and Power buttons together.
8. Press Volume UP and you’ll be in Download mode.
9. Plug in your device to your PC using the USB cable that came with it.
10. Click on Start in the Odin and it’ll start flashing Stock Firmware on your device.
11. When the firmware’s flashed, your device should automatically reboot.
12. You’re all done!
Congrats! Your Verizon Samsung Galaxy Note 4 is now unrooted and is running the official stock firmware.