ArcGIS Online does not have a blank basemap by design. However, users can create an empty basemap and add it to the basemap gallery.
The instructions provided describe how to create a blank basemap and add it to the basemap gallery in ArcGIS Online.
Note: All basemaps added to the gallery must have the same spatial reference. To achieve this, add basemaps in any spatial reference as long as all the items added to the gallery share that spatial reference. To achieve the best performance, it is recommended that all basemaps added to the gallery are cached (tiled) layers.
In ArcMap, create a polygon shapefile using the Web Mercator coordinate system and save the map.
a. Follow the defaults for publishing options, except for caching. b. Instead of drawing the map service dynamically from the data, select 'Using tiles from a cache', and select the same tiling scheme as ArcGIS Online.
c. Publish the service to get a blank tiled map service.
In ArcGIS Online, add the tiled map service to the basemap collection. To do this, create a group in the ArcGIS Online organizational account, and add all organizational users to the group.
Create a new map in the ArcGIS Online map viewer.
Add the tiled map service to the map viewer.
a. Click Add > Add Layer from Web, and add the new blank map service by copying the blank tiled map service URL from ArcGIS for Server.
b. Check the 'Use as Basemap' option. Now, an empty map with a blank basemap appears. c. Save the map as a blank basemap, and share it with the group created for the organization in Step 3.
This blank basemap must show up as one of the available basemaps for the organizational users. Edit the Organization's settings in ArcGIS Online to make this happen.
a. Navigate to My Organization > Edit Settings > Map. b. Under Basemap Gallery, select to use the basemaps from the group that was created.
Note: Any maps that shared with this group that contain only a basemap layer, will be added to the basemaps for this group.
c. Select the option, 'Share the Esri default basemaps to this group when you click Save' so that the default basemaps still show up as available options for the organizational users.
Edit all ArcGIS Online maps to use the blank basemap. Now, the maps load with a blank basemap, and users have the option to select another basemap when needed.
Note: Users also have another option to set the transparency levels on the ArcGIS Online default basemap to 100% (transparent) to make the basemap invisible.