You can adjust the column width and remove unused column of the line item in document.
Click menu "Document Settings", choose document type and choose "Design".
Document Design Windows will be shown. On the left, click to change to Line Item section.
There are two parts: Columns and Total Section. You can check the box to enable the column or uncheck the box to disable the column. Specify the width of the column under its name. The width of Product column will be adjusted automatically.
In the Total Section, you can uncheck the box to disable the unnecessary column.