RE: Process Workflow field references in e-mail
I'm not sure if this is the "Correct" method but here is what I have found works for me!
If you are using a template, create it first and then save before adding any content. In the 2016 version, to embed field references, click in the template where you want the reference and then click insert/Update. Use the drop downs to select a data element. I found the Data Field Values window to be confusing, so I just insert one field at a time rather than try to string them together and use the Up/Down buttons. Also, if you are using an email template, be sure it was created for the correct entity. For instance, if your email is about an Opportunity, a Global Template probably won't be convenient and easily provide the fields you want to reference.
If you are not using a Template, in your Workflow's 'Send Email' row, click the Set Properties button and look to the right at the "Look for:". Select the entity in the first drop down and the field in the second drop down. Then click Add, which makes the reference appear in the box on the right. Highlight the reference by clicking on it. Then click in the email field where you want to insert the reference and then click OK on the right side, under the Default Value field. Your reference should appear where you were in the email.
Best of luck to you!