If you are using DocuSign for sending documents for eSignature and don’t want to switch to our own eSignature app RS Signature, then you can still use RS Documents to generate a PDF and attach it to the record.  Then when you click the button to send a document using DocuSign you can select the PDF that is attached to the record to send for signature.  Then within the DocuSign UI just add the location for the signature on the PDF.
If you are looking for a one click solution to generate and send for signature then consider using our other RS Signature with RS Documents. Cost for RS Signature app is same price as RS Documents which is only $5/user/month.