Add an Image to the scene
Right click Canvas -> UI -> Image
Set the alignment of your newly added Image object
Press Alt and the bottom right option to expand the Image object to fill the space
Expand the image to the extents of the workspace.
You now have a white background. To learn more about anchoring and aligning objects using the RectTransform, watch this video: https://youtu.be/FeheZqu85WI
View your background on the iPad
Select Simulator -> Select iPad Pro 12.9 Verify your background scales correctly in both portrait and landscape by pressing the Rotate button:
