The Toolbox iPad app can only export a canvas as an image. In order to export a canvas, find the icon in the menu at the bottom of your screen, as seen here:
To transfer canvases, restore the old iPad backup from iTunes or iCloud to the new iPad. To do this on iTunes (PC/Mac), backup the old iPad and right click on the new one when connected to restore. Or, restore the iPad in iTunes and select the backup during the setting steps.
Note: A harder way to export a canvas on an iPad is with iExplorer PC/Mac software. Find the SQLite in app data and transfer it between iPads.