A method of conducting and on-line transaction. A user at a PC (302) of a first location completes a profile information sheet and transmits it across a secure network (2708) to a central registration server (2704) at a second location also disposed on the network (306). The central registration server (2704) transmits a unique bar code and associated unique ID back to the user PC (302) at the first location, in response to the user sending the completed profile information sheet to the registration server (2704). When the user accesses a vendor server (2700) disposed on the network (306) for the purchase of products and/or services, the user transmits the bar code to the vendor server (2700) when prompted to complete a vendor payment form. The vendor server (2700) sends the bar code to the central registration server (2704) where the bar code is matched to the user profile information. The profile information is returned to the vendor server (2700) and automatically inserted into the vendor payment form. The vendor server then processes the transaction according to the credit information provided. Some or all fields of the vendor payment form are inserted with encoded information depending upon the user selecting a standard or invisible mode of payment, respectively. The payment form is then presented to the user at the user PC (302) for acceptance or rejection of the transaction.