Right now, you will have to assign metadata to the document either in a save to repository task or a workflow between the submitted form with the uploaded document and reviewing the form fields extracted from the document.

The "assign metadata" step can make use of smart fields to extract data directly from the document so you can map it back to the form field.

We are actively working on enabling lookup rules to interact with Laserfiche AI so you can pass a document to the lookup rule and extract fields from it all in one go.