Updated for 7.0
Search member (see: Search Members).
Select View in the top right corner of the pop up. This will take you here:
Select the Accounting tab. This will take you here:
Select the invoice that you wish to delete. A pop will appear that looks like this:
In the top right corner of the pop up, select the green button titled Edit. This will take you here:
At the bottom of the screen, select the red button titled Delete Invoice. A new box will appear that looks like this:
Within the red box, type YES.
Once you have typed in YES, a red box will appear that says Delete. It will look like this:
Select the red box titled Delete.
This will delete the entire invoice.
These are samples.