Commission fees are payable to the employees and must therefore be set up to ensure correct financial posting to the appropriate accounts in the General ledger. This is done in the Commission posting page. Review the setup that is available for the current company. Typically, the commission amounts are posted to a dedicated expense account and are offset to a dedicated payable account. If you don't have the commission posting rules set up, the system will fail to complete invoicing of a sales order which has eligible commissions.
Affiliate marketing is commonly confused with referral marketing, as both forms of marketing use third parties to drive sales to the retailer. The two forms of marketing are differentiated, however, in how they drive sales, where affiliate marketing relies purely on financial motivations, while referral marketing relies more on trust and personal relationships.