In NAV 2017, Microsoft have added new field in Sales Area i.e. Work Description, which help users to add details about the Sales Quote and which gets copied over to Sales Invoice.
This is the important field for the Sales people to give special instructions which can be used for Production if the goods are to be produced or for Stores department or Dispatch department for trading goods. The field is used to stored detailed information about the Order.
There is no limitation on number of characters and it gets copied over to Posted Sales Invoice.
It is a small feature in the system introduced in NAV 2017 but can be very useful.