Your workspace: the canvas
The canvas is your workspace, where all the page layout editing and creation occurs. Drag a text box, image icon, or app icon from the toolbar to place an additional item in the page.
Headers and footers are placed into separate canvases so a page can be made up of multiple editable areas. You can't drag content between canvases but you can copy to the clipboard from one canvas and then paste to another.
Right-click within the canvas and choose Canvas > Edit canvas to change its background colour or add a background image.