How do I remove the banner from my facebook app

For you as an admin of the facebook page, when you use the Free version of Decor this is what it looks like before upgrading.

After you have upgraded your account to any plan the Banner will be removed as seen under. The Admin Panel will still be seen for the admins of the Facebook page. This Admin panel makes it easy for you as an content creator to make changes to the specific app.

Your visitors will be seeing the content created, without a banner after upgrading.