Does ShipLeap transmit commercial invoices to UPS electronically?

Yes. ShipLeap does transmit the commercial invoices and customs information electronically whenever possible by default. 

There are certain countries where UPS does not accept electronic transmission, and in those cases, you will need to print off the commercial invoice and affix it to the parcel. However, it's a good idea in general to include a physical commercial invoice on all shipments, just in case of any issues.