If you use WordBoard on an iPhone and an iPad, you do not need to buy Pro twice or rebuild your keys from scratch on the second device. Here is what actually carries over automatically, what you back up manually, and how to move keys between devices.
WordBoard Pro is a single purchase tied to your Apple ID, so it unlocks on both iPhone and iPad at no extra cost once you restore it on the second device. Your keys are not copied over automatically the moment you install the app. To bring them across, use iCloud Cloud Backups to restore or merge your full set, or export and share individual keys manually.
WordBoard Pro does not require a second purchase for a second device. As long as you are signed in to the same Apple ID (called an iTunes account in the restore flow) on both your iPhone and iPad, you can unlock Pro on the new device using Restore Purchases instead of buying again.
Restoring your purchase unlocks Pro features, but it does not by itself bring across the keys, folders, and templates you built on your first device. WordBoard gives you two ways to do that, and they solve slightly different problems.
WordBoard can back up your keys to iCloud and restore them on another device. Go to the More tab, then Cloud Backups, to find a backup and either merge it with what is already on the new device or replace the device's keys with the backup entirely. This is the right option when you want your whole keyboard, folders included, moved over in one go.
If you only want to bring across a handful of keys, rather than your entire library, export them instead. Tap the plus button in the top right, then Export, and choose how to share the resulting file. On the receiving device, open the shared file and select Copy to WordBoard to import it. This is useful for sharing a folder of templates with a teammate, not just moving your own keys between your own devices.
Not quite, and it is worth being clear about the difference. WordBoard's iCloud backups and manual export are both something you trigger yourself: back up when you want a snapshot saved, restore or merge when you want it applied to a device. Keys you add on your iPhone do not silently and instantly appear on your iPad in the background. If you add a lot of new keys on one device, get in the habit of taking a fresh backup before you sit down at the other one.