To transfer your data to another iOS device you can either create an account on Clue and log in from the other device, or you can move your data using the Backup/Restore feature.
(When you log in on your new device, make sure you wait until you see your data appear before closing the app.)
Both options are also useful for making sure you have a backup of your data in case you lose or change your device.
You can log in to your Clue account on an Android device, too.
If you don't have an account, you can export your iOS data using the Backup feature, then import it into your Clue Android app using the Restore function.