Let me share some insights about the import process in QBO. When importing invoices, you can only send the following information.
Name
Company
Customer Type
Email
Phone
Mobile Fax
Website
Street City
State
ZIP
Country
Opening Balance
Date
Resale Number
As a workaround, manually enter the shipping income in your company or use a third-party app to import the information. You can visit the QuickBooks Apps Center to find one that meets your business needs. All you have to do is enter a keyword in the Search field or use the Categories option to expedite the process.
You can consider following the suggestions I shared above to add the reference number. I’m also adding some articles that provide an overview of how to perform the following tasks.