If you need to charge your customers a one off charge when they sign an agreement, (e.g.: refurbishments, services, etc), you can add it to your licence directly.
On the Licence Editing Page, you will find a section called: 'Additional Charges to Initial Invoice'. Here is where you can click 'Add Charge' to continue.
On the next screen, select the product / service you need to charge for, and add a reference text if needed. Select the tax, then the period for which you are applying the charge (e.g. the first month of the Licence). Adjust the quantity and the amount as needed. (The Amount will be auto-populated from the Product).
Save your charge when you are ready. The charge will now be listed on your Licence and will appear on the customer's first invoice.