Check the Original Purchase Account
On your iPad, make sure the App Store is signed in with the Apple Account used for the original purchase, then open the product page or your purchase history. If you already own the app, use the store’s redownload option. If a price still appears, don’t confirm another payment yet; first check the account under Media & Purchases and verify the original transaction.
Available storage and screen layout may differ between iPadOS and iPhone, but the interface labels remain the best guide: Home, Config, Add Server, and Settings. Don’t rely only on whether a button appears on the left or right in a tutorial screenshot; confirm the current screen name and the fields you need.
Installing the app on iPad does not automatically transfer your connection configuration to iPhone. Check the server list, active Config, Global Routing, and VPN permission on each device before testing the connection. Check the App Store listing for system requirements.