How to delete or modify an invoice item

Choose "Add items to invoice"
Go to Command bar > "Data"
Click "Edit" button next to the item record you want to change, choose "Delete" or "Modify"

Technical notes:

Avoid manually changing the "invoice number" at the item level
Items are linked to its respective invoice by the "record key", not by the item level "invoice number"
If you wish to "re-assign" items to a new invoice, please delete associated items linked to the existing invoice and then re-add the items to the new invoice by going to "Add items to invoice"