In Lightspeed R-Series when creating a new sale you can add a new serial number to a product and once the invoice is created the serial number will export with the product to QuoteMachine. You can do so by following the steps elaborated below.
If you need a refresher on how to use serial numbers in QuoteMachine check out this article.
Create a new sale in Lightspeed, add a customer, then add a serialized product, enter the serial number, and then create the invoice as you normally would.
If we take a look at the "Extreme Cat Eye" product in QuoteMachine before we create the invoice. We see that there are no serial numbers under this product.
Once the invoice is exported to QuoteMachine, the serial number gets exported along with it. You're also able to view which document is attached to the serialized product.