Explanation

Box 1: Fill
Scenario: You must display a visual indicator in the app so that sales representatives know whether the app is offline before submitting reports.
Fill - The background color of a control.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/controls/control-screen
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-form