In order to add an unsubscribe link to a campaign email, you must check this box in step 2 of the campaign as seen in the screenshot below:
NOTE: If you are using a pre-configured email template then the unsubscribe link must be set up as per usual according to the required steps for the WYSIWYG editor.
Click below and select "How do I configure the unsubscribe hyperlink in the text editor for email templates" in order to view:
https://support.punchh.com/hc/en-us/search?utf8=%E2%9C%93&query=unsubscribe