OpenVPN Connect is the « official » application from OpenVPN Inc. and is designed to be more user-friendly for VPN users with limited technical knowledge. It’s not as feature-rich as openvpn for Android, which is targeted towards more advanced OpenVPN users.
Openvpn for Android is a free and open-source client created by Arne Schwabe which allows you to connect to any VPN service that supports the OpenVPN protocol. If your device doesn’t support the pre-configured VPN applications that are available in the Google Play Store, this is an excellent alternative. The process is relatively simple. It is necessary to import the VPN profile files. (The configuration files are named.ovpn). These files can be downloaded from the provider’s site or by contacting live chat support.
After you’ve imported a profile, simply tap on a server in the list to connect to that one. Once connected you’ll notice that your Internet traffic is sent through a secure tunnel to the server selected in the application. You can see your connection’s status and details in the Status tab. A kill switch is activated by default, and it will shut down your Internet connections when the VPN tunnel drops.
The app offers a per-app VPN as and an option to be always on that you can find out more automatically establishes an automatic VPN connection each time the app is opened and keeps it running even after your device has shut down or switched networks. The latter however requires Android 7.0 or higher and may drain your batteries more than usual.