Invoice in view mode provides an overview of the invoice, as well as the option to change the status of the invoice. If the invoice is saved from a work order, there is also, for example, a link for direct access to the work order from this screen.
Refresh [Comments]: This button allows you to retrieve comments that are on current work orders. Assumes that this 'Comments → Invoice' is activated in the system settings 16.1.0 System Settings.