When you have inventory sold that you need to dropship, use the Sales / Inventory grid to retreive the airbill in order to print it and ship the tickets for that invoice.
In the portal, click SALES then INVOICES to filter by the invoice you want the airbill for.
Please ship same day or the next business day, making sure UPS of FedEx pickup is scheduled for that location.
Some exchanges (TicketNetwork and broker-to-broker) require support to manually retreive the airbill and send it to you. Please open a support ticket in those cases.