Ensure that Zoho Sign’s extension has been installed in Zoho CRM’s marketplace, see here.
Verify that the plugin is connected to Zoho Sign, see here.
Important notes about this integration:
The document needs to be fully executed and signed by all parties in order to be available for download by the plugin User (the User will be able to see a list of related documents).
Navigate to Customization - Zoho Sign and enable the “Show in user portal” for Zoho Sign documents to display to Users as a menu item.