Elevation can have an impact on your vehicle's range, using more energy driving up steep terrain. Taking changes in elevation along your route into account will help to plan out expected range.
After creating a new trip and selecting your route, tap on the first station icon you want to add to your trip:
Then tap on the elevation profile icon located above the filter options icon. You can view an elevation profile for each leg of your trip:
To learn more about how to use Trip Planner for iOS please visit this FAQ: Trip Planner for iOS