Adding column

[Ealfardan]

This should help you with the serial numbers

@Tut

If you mean line item numbers, see https://www.manager.io/guides/10303 .

If you mean adding the serial number of a product being sold, use a line item custom field. See https://www.manager.io/guides/10411 .

This theme is before improved support for RTL, so you might need to modify it for better RTL support.

For splitting the Qty and UOM columns, you can do that in themes but you’ll need to hire a developer.