Adding Dropdown Options in Forms to send more information with an order?

Hi, I'm trying to find out how to put some extra dropdown options into the Payment forms. Just to allow extra choices to be made and sent with the order. Is this possible and could you steer me in the right direction for which files to modify.

Do I just add extra dropdown options to the form and it will be sent or do I need to modify extra files to make sure the extra options are included in the order ?

Cheers
J#xx

You should elaborate on what extra options and what you want to do with them.

As most all order details are stored in the database any extras currently have no place to be stored and no code to capture them
So code to capture them and DB alterations to house them might be in order

Thanks for the reply, I've been instructed to include prescription details for Glasses there are quite a few choices available all with +/- options. I hoped to be able to have a seperate page dedicated to these choices somewhere between going to the checkout and the order confirmation page. It sounds like it could be very technical.

Cheers
J#xx