The easiest way to re-brand the app with your wording and graphics is to just customise the app from My Account.

The app within the app store will still show FormsFly, but within will be your logo and company name.

If the app store logo and naming is important then the cost is much greater as there is more work in setting up a new brand this way along with subsequently submitting the app to Google and/or Apple as a separate app. This would be more suitable for large scale corporations.