1. Create a custom Field in QB items. Open any Customer in QB>Click on Additional Info> Define Fields>Enter in the Customer field label for Sales Order # and click on use for Customer.
2. In the QB invoice, go to the Formatting Tab and select to Customize the Data Layout. There you will see several tabs. Under the Header Tab, find the custom field that you just created for the Sales Order # and check the book to see on the Screen and Print. Click OK to save the changes to the format.
3. In All Orders, go to the menu Company and QB Synchronization. Select the SO/Shipping tab.
The SO/Shipping tab sports four drop-down lists. With them, you can associate an appropriate QuickBooks custom field to each of three All Orders fields that do not have a default QB counterpart. That way, when creating a sales order within QB, you can make sure these elements make it into your All Orders sync. Click the refresh button above the drop downs to load them with the latest available fields from Quickbooks.
Click on the Sales Order # Drop down to select the QB Custom Field that you want to map it to.
Note:
The Original Order Quantity, as well as the Back Order Quantity fields, can be mapped to custom item fields within QuickBooks, whereas the Sales Order # and Tracking # can be mapped to a custom customer field.
4. Create a Sales Order in All Orders and then Ship it and Sync it to Quickbooks.