How to attach document with Export Invoice?

When creating an Export invoice, there is an option to upload the document. Click on Upload Document.

Option of Uploading Document will show the number of documents attached and if you want to delete the attached document then click on the delete button. After that save the Invoice as Approve.

From the listing page of Invoice, open an Awaiting Receipt Export Invoice in View mode and click on the uploaded document then it will show the attached document. If you want to see the attached document then click on view.