Information from your item's profile and contact information from your company profile are printed on system-generated for redemption purposes, so please make sure it is correct for whomever receives the certificate.
You can see a sample of your certificate at any time by going to your item's profile and clicking the "Download Sample Certificate" button toward the top center (between "Edit" and "Campaigns").
"Detailed Item Description" and "Certificate Redemption Instructions" ARE printed on certificates.
"Special Instructions" are NOT printed on certificates. This field is available in case special requirements or handling instructions need to be communicated to everyone who sees your listing. Some examples are: "For auctions only, please do not use in raffles," or "Minimum bid $20," etc.