You wish to capture specific information from your registrants.
Your service can be configured to capture a number of commonly used registration fields, such as Company, Handicap (for golf), Emergency Name and Phone, etc.
Please go to Website -> Fields, and look for the field in question on this page. For each of the defined fields, you can set them to Required, Optional or Do Not Show. The setting of this field will define whether or not you want to capture these fields for each registrant.