If you have an active subscription, cancel it first before deleting your account.
If you subscribed through Google Play or the App Store, the subscription must be cancelled from your mobile device's subscription settings.
Once your subscription is cancelled, you can delete your user account.
Open the NaturalReader app and select Account from the app menu.
Select Edit
Select Delete My Account
If you are sure you want to proceed with the deletion, select Delete My Account to confirm
Your account will be deleted and all relevant data removed