Ticket sales let guests pay for their spot when they sign up through Invitations. You connect a payment service provider account once, set a price and tax per guest list in your event (see Manage event ticketing and QR codes), and every ticket sold adds a guest to the event.
The Sales section is where you support your buyers: find an order, check its tickets, resend the confirmation, refund all or part of it, and download the invoices and credit invoices your account has issued.