For a corporate guest, usually they require you to invoice their company for accommodation (and sometimes for the extras). In order to create this invoice and have it addressed to the company, you need to set them up as an Agent. The instructions on how to do that is here.
You'll need to create your guest's company as an Agent in Preno - Add the corporate agent name and set the commission as 0%
Creating the invoice:
When you go to add payment for a booking, just select the payment type of Invoice Agent through the dropdown. It'll come up the accommodation amount preloaded. Just click Add, and then Preno will raise a draft invoice in Xero for you to send off!