May I know how I can ad banner in mendix?
Is it some html code that should be shown? You could use the html snippet widget to do this.
If you want to use it in all of your pages, you should think about to add it to your main templates.
Don't know what you exact goal and usecase are but take a look at the html/java script snippet from the appstore: https://appstore.home.mendix.com/link/app/56/
You should be able to do something with ad banners with this.