A method of enabling user interaction with computer software including, in a computer system, transferring print data to a printer, printing a form responsive to the print data by printing information indicative of a text field coincident with coded data indicative of the text field, so that when a sensing device is moved relative to the text field the sensing device can sense the coded data and generate the indicating data indicative of its movement relative to the text field, using the indicating data to determine the movement and then perform an action associated with the text field based on the movement. The computer system determines a handwritten signature using the movement, determines a predetermined signature using a user identity, and verifies the user by comparing the signatures.