Manual invoicing is possible from the administration portal. It looks identical to what any customer would see, however hidden products will be displayed and you will be able to select which customer you attach it to on the final step.
The first screen shows you all available packages and allows you to select the number of licenses for each either by typing int he input box the number or pressing the increase or decrease buttons (+/-). Whenever you move to the next section or back it will dynamically update the summary on the second tab.
The second section will give you the ability to see in a table view all of the packages attached to this order, it's total with any discount codes. You can enter working discount codes which will apply the discount to the subtotal and adjust the VAT and total accordingly, or if an invalid discount code is applied it will give back the visual feedback that the code is not accepted.
Moving onto the final tab administrators will see two dropdowns. The customer dropdown will show all customers. Individual customers by their names or organisations by organisation name - (lead contact). Allowing you to type quickly to skip through a long list.
The second option is the invoice type, manual will create an unpaid invoice (which will not be emailed out) which they are able to pay via PayPal or an administrator can mark as paid from within the invoice screen. Or undocumented which will be hidden from the user but will automatically allocate licenses (and for individuals automatically allocate them).