How do I use it to sign documents?

Scriptel signature pads plug into the USB port of your computer. The mobile device virtually plugs into your USB port through the mSign Desktop application running in the toolbar. Once the mobile device is paired to the desktop application, your mSign signature pad is “plugged in.” Any application that runs with a physical pad now runs with your mobile device.

Please see the following guides:

Scriptel Hardware

A Brief History