If you have an invoice with multiple lines that should all have the same coding, you can copy an existing line in the middle (line) pane. There is no restriction as to the number of copied lines.
1.Enter the first line by clicking the New line icon, 
, and completing the bottom (details) pane.
2.Click to select the check box at the beginning of the line to be copied.
3.Click the Copy line icon,
, to create a new line that is identical to the existing line.
Note: Not only is the new line an exact duplicate of the existing line, but all the fields in the bottom (detail) pane are also replicated.