Just follow this step-by-step tutorial to find out how to turn off VPN on your Mac.
If you are using a third-party app from a VPN provider, simply open the VPN app and click on Disconnect (or a similar button or on/off switch).
If you have created the VPN connection manually or if you don't manage to turn off the VPN from the VPN app, follow the steps below.
Choose Apple menu > System Preferences.
Go to Network.
Choose the VPN connection from the left column and click on Disconnect button.