The QR code appears on a page appended to your signed document. It embeds a link you can use to navigate back to Legalesign to affirm the document later. PDF Certification now largely obviates this feature, but it can be a secondary or back up means of document authentication.
Admins can change the team default to remove it. Go to Admin > PDF Security find the entry for Append Legalesign validation and signer info, untick the checkbox and save.
You can access and export an audit log of a signed document anytime by going to a document details page (click on document title in the dashboard or archive), and then scroll to Audit Log. Click the option Audit Log only PDF download.