If you need to unpublish an invoice to republish or to make edits, then there are three ways to do this:
From the Inbox:
To unpublish an invoice from the inbox, click the green tick icon as shown below. A pop up window will show asking you to confirm this action.
From the View screen:
When on the view screen of a published invoice, the publish button will be greyed out. To the right of this, there is an unpublish button (shown below).
If you need to unpublish more than one invoice, you can do so in bulk. To do this, tick the boxes beside each invoice you wish to unpublish and then choose the Unpublish option from the Actions menu that will appear.