Purpose and benefits
With area wise filter in sales bill, we can select the customers based on their respective area, when the option is enabled, while making sales bill it will be listed with the area, once we select respective area it will show the customers mapped with that particular area.
To enable the option Click on
Tools-->options-->options--
Search for "Area LOV for customer filter" and enable the same, then click on save.
Now in the sales bill screen, it will show area names before selecting the customer.