A GS1 Company Prefix is a number that is unique to each member of GS1 US and is assigned by GS1 US. The GS1 Company Prefix identifies you as the owner of your brand and is used in populating your company's GTINs (Global Trade Item Number) and GLNs (Global Location Number).
iFoodDS is not requiring your GS1 Company Prefix(s) to set up your account; however, it is preferrable that you include your GS1 Company Prefix on your company account in iFoodDS. Having your GS1 Company Prefix(s) associated to your company account will assist in traceability of products and confirmation of GTIN and GLN ownership.
Visit the GS1 website to learn more about the GS1 prefix. Go here to set one up for your company.