When you are invoicing a customer, you can also include unbilled expenses and projects corresponding to that customer in the same invoice.
You will find the unbilled expenses and projects of the customer displayed right below the line items.
Click the unbilled expense/unbilled project. Check the expenses/projects you want to include in the invoice from the popup and click Add.
You will find that the unbilled expense/project to be included in the invoice as a line item.
Online accounting software
for small businesses.