Custom code pockets

It would be a great idea to have the possibility of managing in the backend, pockets to add custom code. For example, to be able to add in different sections of the site custom banners, integrated advertising with Google Ad Server or any type of custom code. Also, Have a choice to decide where in the layout of the front end of the site it should appear.

Thanks to all

You can do this under Customize > Themes. Either directly there in Edit CSS/HTML, or in a component that you can add to your default theme.