In the DocuGen Sign item view, expand the "Document" accordion:

You can provide .docx and PDF documents for signature in one of two ways:

1. Upload file allows you to upload a PDF or .docx 
2. Catch from a Files column allows you to get the document from any Files column

Upload file

This is useful if the document that will need to be signed will not change from one signer to another. For example, your document might be a standard contract (e.g., a non-disclosure agreement) where the contents are the same every time, except perhaps for the signer's name, signature, and date.

Once you select "Upload file", you will see a button to upload your document. You can upload PDF or .docx documents.

Catch from a Files column

Use this option if your document may change from one signer to another. For example, you might want to send a sales order to customer A and a lease agreement to customer B on a different row in your board. 

Once you select "Catch from a Files column", you will need to select the Files column to use from the dropdown.

You are now ready to define the signers.