The primary location is used, by default, when creating Purchase Orders or Sales Orders in QuickBooks Commerce.
To change the primary location:
Select Settings and click on Configuration. The 'Default Settings' will be displayed.
Scroll down, and you will see the Primary Location Tab, which shows all the locations created for your company. This will be the default location when dealing with stock.
Identify the location that you would like to make the primary location. Choose that specific location to make it the primary.
The selected location is now your new primary location. All Purchase Orders and Sales Orders will be created from this location by default.