Clicking the button at the right of the map screen will open the Base Layer Panel.
From here you can select the design of the base map that you'll be displaying your features on. You can also use the opacity slider at the bottom to fade the map and help your features stand out more. Some of the choices are as follows.
OpenStreetMap Standard (Default)
OpenStreetMap Landscape
OpenStreetMap Humanitarian
OpenStreetMap Cycle
OpenStreetMap Outdoors
OpenStreetMap Transport
OpenStreetMap Transport Dark
Stamen Toner
Stamen WaterColour
Google Hybrid
Google Satellite
Bing Road
Bing Hybrid
Bing Aerial
There is also the Blank base layer that displays no map, just your features on a white screen.
Note: The look and details of these maps can change as you zoom in and out. Experiment with them to find the best one to display your information.