I'm trying to do Embedded Signing and I want to send the email to the Signers myself instead of having DocuSign send it.
I've found this post: Docusign email notification for embedded signing case
That describes two parameters. I have not been able to find the second one (Use Envelope Complete Email for (non-suppressed) Embedded Signers) in my testing account.
Is this option no longer available? Is there any other way to achieve the same result?
For embedded signers DocuSign will never send an email letting the signer know they have a document awaiting signature. The two emails that are sent can either be Signature Notification and/or Completion email. Signature Notification is sent to the signer immediately after signing, while Completion emails are sent all at once only at the end when the last signer completes the envelope.
The options are both still available in the classic UI under Preferences --> Features. 
If you are using the New DocuSign Experience then follow the instructions here
See the Document delivery section.
