NordVPN software can usually be uninstalled the same way most software is removed in your Operating System. Here's how:
Microsoft has an always-up-to-date article on how to uninstall software here: https://support.microsoft.com/en-us/instantanswers/ce7ba88b-4e95-4354-b807-35732db36c4d/repair-or-remove-programs
Google has an always-up-to-date article on how to uninstall software here: https://support.google.com/googleplay/answer/2521768
Connections that do not use the NordVPN app may require different steps in removing them. Usually, it's simply to remove all the settings you entered, and change back any you have changed. If you need help, do not hesitate to contact our support team for help!