If you forgot to add your expenses to this invoice, unfortunately, they cannot be added after the invoice is paid. However, you can add them to your next invoice and get them retroactively.
What you need to do to add the expenses to the system is:
1. Log in and go to invoices page
2. Press the invoice the expenses belong to
3. Scroll down and press the button "Edit expenses" or "Add expenses"
4. Add your expenses to their respective categories for an example: one row for Kilometer expenses and one row for Meal expenses
5.Scroll down and press "Update expense"
Expenses will be on draft status as long as your salary has been paid for you.
You are done.
Note: You cannot take advance salary from expenses.