Install OpenVPN Connect
Get OpenVPN Connect from the App Store, then open it.
Download the iPhone and iPad appOPENVPN SETUP
Install OpenVPN on iPhone and iPad
Set up OpenVPN Connect on your iPhone or iPad in three steps.
Import your VPN file
Save the downloaded .ovpn file in Files. In OpenVPN Connect, tap Add, then File. Select the file and confirm the import.
Connect
Tap the switch beside your imported profile. Enter your VPNNu username and password if asked, then allow iOS to add the VPN configuration.