In the invoice window there is the History section under the invoice header.

To show / hide the section, click  in the black menu column

To expand / minimize the section, click / 

The History section contains the steps the invoice has passed in the flow and the step where the invoice is located is green:

If you want more information about a step, you can click on that box and thereby open a form that shows the following:

• Addressee: The person who received the invoice in the current step.
• Added by: Who sent to the recipient.
• Added: When the invoice was sent to the step.
• Status: Not Handled or Sent.
• Sent by: Who sent from the current step. If a replacement has handled the invoice, this will be displayed here.
• Date: When the invoice was sent from the step.