Using a VPN app on an iPhone is very straightforward. First, download a VPN app of your choice from the Apple App Store. After installation, open the app and follow the on-screen instructions, which usually involve creating an account or logging in. You will then be prompted to allow the app to add VPN configurations to your iPhone—you must tap "Allow" and use your passcode or Face ID to confirm. Once set up, simply open the app and tap a large "Connect" button. The app will connect to a recommended server, and you'll see a "VPN" indicator appear in your status bar, confirming your connection is secure.