When you’re working on an official project, you might incur an expense on behalf of the customer. You can attach the expenses to an invoice if your customer has agreed to pay for your expenses such as labor costs, travel expense..,etc.
Prerequisite: Mark your expenses as billable to associate the expense to an invoice.
To attach expenses to an invoice:
You can add up to 200 expenses to an invoice.
Books
Online accounting software
for small businesses.