You can set your device to notify you when your faxes complete, so that you don't have to wait around watching the app while the fax is pending. You'll get a brief sound (or vibration, depending on your volume control setting) and a brief message in your notification center, if you turn notifications for JotNot Fax on.
The first time JotNot Fax starts up, you will get a popup alert asking whether you'd like to allow these notifications. If you agree to allow them then, you won't need to take any further action to turn them on. If you'd like to turn them on at any later point, open Apple's Settings app (icon looks like a gear), navigate to:
Settings > Notifications > JotNot Fax
and make sure that the switches for "Allow Notifications", "Show in Notification Center", "Sounds", and "Show on Lock Screen" are turned on. To turn notifications off, visit Settings > Notifications > JotNot Fax, and set the switch for "Allow Notifications" to off.