Spread Email Marketing Guides:

Add "Click Here" or "Unsubscribe" Link In Your Email

Step1:

Highlight the phrase "Click here";

Step2:

In the drop box from “Spread Link”, choose “Click Here”.
click here

Step3:

3a. Highlight the phrase "Click here" again;
3b. Check from the "Hyperlink Manager" that whether the link is[NEWSLETTER_LINK_URL].
check url
check url

Click to learn How to add Facebook share button in email .