By default you have the Name, Email and Question fields.

These three fields are required to keep on your form if you want to receive missed requests and offline messages.The titles/labels of the name, email and question fields can be changed via the account dashboard.

Additional fields can also be added. Once you login to your account dashboard, go to:

Setup > Messages > Chat Request Form

You may also disable the chat request form on the Generate HTML page. Just check the "Bypass chat request form and send visitors straight to chat" box.

Login to your Account Dashboard here: http://www.onlinechatcenters.com/account