There are too many different clients to list them all, but in essence, we can use any VPN client that supports the OpenVPN protocol. To utilize the latest and most secure encryption techniques, the client must be based on version 2.4 or higher. Some of the more well-known ones include: for Android: OpenVPN Connect and OpenVPN for Android, for iOS: OpenVPN Connect, for macOS: Viscosity, for Linux: OpenVPN client, and for Windows: OpenVPN GUI and Viscosity.