How to install a previously purchased iOS application again?
All applications, including ABBYY applications, which you purchase in App Store are associated with your Apple ID.
To install the purchased application again, please do the following:
Make sure you sign in with Apple ID that you used for the original purchase.
Launch App Store on your mobile device.
- Tap the account icon ( or your photo) in the upper-right corner.
Tap Purchased > Not on this iPhone/iPad.
Find the ABBYY application in the list.
Tap the Download icon.
More information could be found in the following article of Apple Knowledge Base.