One major feature of TypeEngine is that you own your app. This means that you have a direct financial relationship with Apple. The revenue you generate from your app and subscriptions sales get paid to you directly from Apple.
To enjoy those benefits, you need to join the Apple Developer Program. You do not need to be a developer to join the Apple Developer Program. You simply need to join so we can develop on your behalf. The Apple Developer Program costs $99 (USD) per year. To learn more, check out our guide to joining the Apple Developer Program.