GSA Advantage is an ecommerce platform designed primarily for Government buyers to conduct product purchases in relatively small quantities. You must publish your catalog, with all the products you sell on GSA Advantage. As far as service categories, you have a choice to publish them on either GSA Advantage or in the “Text Term and Conditions” file. While publishing them on GSA Advantage increases their visibility, it is still common practice to include service categories just in the T&C file, and publish the file using SIP or EDI.