We got around the problem by using a program called "ShipStation" which imports our orders from our online store Ecwid Shipping Cart. It seamlessly integrates with USPS, FedEx, UPS, and others.

Then we use an app in QuickBooks online called "Synder" which imports all our orders from our online store into Quickbooks online as a "sales receipt".

Once you've got your orders in QuickBooks Online as a sales receipt you can use the QuickBooks online shipping manager if you prefer not to use Shipstation..