The create document, workflow component, Create EML with PDF is the same as the Create PDF email component with two major differences:
The Create PDF email component sends out an email.
The Create EML with PDF document creates an EML file in the payload of the workflow. This EML file represents an email, that could be sent later, but it is not sent until you e.g. run the to email server. You can also e.g. store the email file in the file system with the To filesystem component.