If you wish to send a read only view of a form to an external address, you can do so through the workflow step type called Send existing form (externally). This will display the completed contents of a form in an external users web browser without them needing a Natural HR account.
When doing this, you should be careful to not include any sensitive information in the form and to be careful which email addresses you send the form to through the workflow as you won't be able to recall the email once it has been sent out through the system.
I have setup my workflow above to send out a form to the employees manager. After that, the second step sends this completed form on to an external email address of my choosing. For the send existing form step you will need to reference the workflow step the form has been completed on with the form in step field and then manually enter your external emails as recipients for the completed form.
The email that is sent out to the external email address will include your custom text and branding and also a view button whereby the user can click to view the form in their web browser.