Manually Add Invoice Charges to an Invoice
You can create Named Invoice Charges and manually apply the charges to an invoice.
Go to Billing > Invoices.
Search for the invoice(s). Find the invoice you want to add the charge and click on the actions ellipsis and edit the invoice.
The Edit Invoice windows pop up and you will see a section to Add Charge/Fee to the invoice. Choose your charge from the drop-down list. Click Save once you have added your charges.
You will see the charges applied and the invoice due amount will now reflect the added charges.
Tip
There is a Fees/Charges element you can add to your Invoice Template so they show up on your Invoice PDF.