The document discusses the functions of travel management companies (TMCs). TMCs assist travelers by providing expertise, recommending destinations and services that suit clients' needs, assisting with travel documents, making travel arrangements, and helping with refunds and cancellations. TMCs earn revenue through negotiated professional fees, commissions from suppliers in the form of rate-minus or net-plus agreements, service fees for assisting with documents, and rebates or incentives for booking large groups. The document provides examples of how TMCs earn fees and commissions on bookings.