Enrolment

Hello,
I am currently setting up a moodle site for a retailer education on my companies products. So, the information that we want to collect from the end users is a bit different than what comes standard with moodle. I was looking to see if anyoen could poitn me in the right direction on this. I am familair with html, but not so much with PHP. Am I corret in assuming that it is the "signup_form.php" that needs to be edited? Any suggestions are greatly appriciated.
THNX
JJ