Hi, I want to customize My WebGIS Application interface that has been built WebApp builder throug ArcGIS Portal. How do customise the application interface as per the requirement? Please Guide me if you have any resources??
Are you referring to the theming? As far as I know, custom theme are not supported currently on WAB in portal. Only custom widgets are supported.
You can add theme to the folder in the server however that is not encouraged and supported by Esri.