How can I re-download my purchase from the iOS App Store without having to pay again?
On iPhone, iPad or iPod Touch using iOS 11 or later: Please open the App Store and touch on your small Account icon at the very top right at the Today tab. You’ll see an option to download your previous purchases in the list appearing.
On iPhone, iPad or iPod Touch using iOS 10 or earlier: Open the App Store and select the updates tab at the bottom. Afterwards, you’ll see a Purchases item at the top of the list.