To maintain proper workflow of sale invoices, in which you can add quotation, order, challan and then sale invoice, please follow below steps:
Step 1: Go the the Administration menu
Step 2: Click on the configuration option
Step 3: Click feature/option, open Inventory Tab
Step 4: Enable option regarding sale quotation, sale order and challan processing
Step 5: Select their respective configuration
Step 6: In transaction menu, you will find sale quotation and sale order voucher
Step 7: Add Quotation voucher and pick its refrence in order by using F11 key on item grid lines
Step 8: To add challan, use material issue to party voucher select type as sale challan
Step 9: while generating sale invoice salect type as against challan, it will adjust challan refrence
In this way you can maintain complete workflow for sale booking