Both the web and app auto-save work every 60 seconds. The Save Draft button on the web version of eCompliance appears when you click Submit.
Please note, Save Draft keeps the version on your device only. This means that if you uninstall the app, your form will be deleted, or if you use a second device or desktop the saved draft will not appear.
On the mobile app, the "Save Draft" feature pops up both on the Options menu. The form will be shown in the app as "In Progress" until submitted.