Yes you can change your app in the WYSIWYG editor, save them, and your changes will appear instantly to your users.
For more information, please, read the User Manual.
Anything you want, add buttons, change colors, change how buttons work, content, etc.
Resubmit is a process which is needed to change information about your app in the Apple App Store. It usually takes several days depending on the complexity of the changes you make. Before you hit “resubmit” make sure that is what you need to do, sometimes using the “publish” feature takes care of the changes you have made.
You need to click on Publish button when you want to make the following changes:\n\nApp color theme;\nContent of the tabs and elements (phone number, email, text, Url etc…) and their order in the app;\nThe name of tabs and elements (icons)\n\n\nUsing the “publish” feature is a much faster option as it sends out updates to apps immediately without having to do an app store submission.\n\nYou need to click on the Resubmit when you want to change:\n\nSplash screen, icon;\nName of the app;\nDescription;\nKeywords;\nCategory;\nApp website;\nApp language.\n\n\nIf you add new elements (tabs/buttons) which are not supported by your current app version (new functionality since the last version of your app) you will get the message telling you to Resubmit your app.
You can make changes to your app once it is released either through the “resubmit” or “publish” option depending on the changes you have made.