Ledger is the primary writing application for Senitrus eInk tablets. The device comes with a stylus, and you can write handwritten notes. These notes can be stored in the device, or transferred to a computer for the computer to view, and possibly convert the handwritten text into a document format that you could then hopefully edit. The .ledger file is copied to the computer, and conversion happens. The file is then converted into .rtf which can be read and edited by Senitrus Office. Ledger is supported in computers, and eInk devices.