Secure Link is related to the email authentication for Visitor Access Settings. This is found when you receive an email invite to log in and access a Zoomforth site.
The Secure Link is embedded in the View Site button and is also found on the bottom part of the email if in case the button does not work, as seen in the sample invite below.
Clicking the View Site button or the direct link will open the site in a new tab where the visitor is asked to sign in to view the site.
The visitor should enter the email address that had received the invite to get a code that will be used to log in, otherwise, it will show the message below asking if the visitor needs to Enter a different email address or to Request Access.