I love the idea of being able to send estimates/invoices for eSigning. However, I feel the usefulness of this is limited because customers must first sign up for the client portal and navigate through the portal to find the estimate and eSign it. The portal lacks customizability and using it could be confusing for customers who just need to sign a document. I would suggest keeping this functionality intact for those who use the portal, but adding document eSigning for customers who don't have access to the portal. It would function much like the native Zoho Sign process. The customer clicks the sign/approve link in the email and it brings up Zoho Sign, where he/she can review the document and quickly eSign. In my experience, this would be much more helpful than currently implemented.

I'm not a developer, but I would think adding the non-portal signing option would be fairly simple, as this would simply tap into Zoho Sign's current functionality. Books could just send the document and customer information to Sign, where Sign could send the document as part of its normal functionality. As of now, I must download every estimate as a PDF from Books and upload to Sign as a new document, coping over customer information, etc. It would also be extremely helpful for Sign to tell Books when an invoice has been approved/signed. Similar workflows could be dramatically improved by this integration.