You'll need to do this when you have a booking from an agent. You can set one up in the Agents tab. If you're using the Xero integration, this will create an invoice in Xero for you to email. The email address you use for the agent will automatically be pulled into the invoice.
If your booking came through your channel manager, it'll have the correct source selected already. You might need to double check your list of agents to ensure that the right agent type has been set.
Invoicing the Agent for accommodation
When you create an Agent invoice with Preno, this counts as a payment against the booking. When you add the payment, Preno will automatically enter the value of the booking without extras.
Preno creates the draft invoice in Xero for you to approve and send off to the agent. If there is any, the agent commission will be already subtracted. The contact that the agent is addressed to will have the name and e-mail address that you entered when you created the agent in Preno
The guest can now pay for any of their extras and incidentals, using the payment method that they'd like. Agent commission won't come out of any extras.
Invoicing the Agent for guest extras
Is your agent paying for both the guest's accommodation and for their extras?
When you're adding the extra to the booking, a new checkbox will appear called Bill to agent (not guests). When you tick that, the extra will be added to the agent's invoice when it gets created. This won't change the invoice if it's already been created - you'll need to create a new invoice to have the extras included.
When you invoice the agent for the guest's extras, Preno will subtract the agent's commission out of the extra too. This can't be changed - extras invoiced to an agent will use the same commission amount as the accommodation would be.