An invoice can be edited simply by editing notes (time/expense entries). Alternatively, the invoice may be deleted and recreated. After editing one or more notes that were previously added to the invoice, simply download the invoice again. No other action is needed. 

Note that a note included in the invoice cannot be removed from the invoice. If there is a need to remove a note from the invoice, delete the invoice, then delete the note and recreate the invoice.

Invoice Date may be changed by clicking on Invoice Date in the listing of invoices in Cases (Projects) or Clients tabs.

Adding/Altering Discount ** Please do not alter discount if tax is being charged. Instead, delete the invoice and recreate **. Discount may be added (or altered) to an invoice by clickon on View Invoice icon  (the first icon in the invoice list line), then entering a new discount on the simplistic invoice view screen.