As an administrator of an organization, you can configure your ArcGIS Online website to showcase the geographic information that's important to the organization. You can configure general settings such as adding a logo and specifying whether or not members can search for content outside the organization. You can also configure the home page, the gallery, the map, item details, groups, utility services, roles, credits, and security and enable Open Data. Some configuration is done as part of the subscription activation, for example, setting up your organization's URL. Only default administrators can configure the website; custom roles do not have this privilege.
Use groups to configure site
Groups are a way to organize and share content around a specific topic or common activity. You also use them to configure your organization's featured content, basemaps, and app galleries. After you've activated your subscription and configured general settings for your organization, you should consider setting up groups to use for the rest of the site configuration.
The first step is to create groups for each area of the site where you want custom content. This might include a group for the home page, gallery, basemaps, Map Viewer app gallery, and group app gallery. Give your groups the status of organization or public so they appear in the list of groups for each configuration setting. Private groups won't appear in the lists.
The next step is to share items to the group you've created. Each item should be shared with the organization and, if you allow anonymous access, shared with everybody (public). You can create and share your own maps, basemaps, apps, and so on. You can also share public items you find in ArcGIS Online, including Living Atlas basemaps and configurable apps.
The last step is to select the group you want in each part of the site configuration; for example, you can configure the map to use your basemap group. As part of the configuration, you can choose to add the Esri default basemaps or apps to your group, and update the sort field and order of the items in the group (you initially select the sort field and order when you create your group). Now that you have set up groups for the site configuration, going forward, you can manage content through the groups; for example, you can add and remove the specific maps and apps you feature on the home page.