In Copilot, all marketing emails to customers will automatically have a "click to unsubscribe" link.

It is determined a marketing (mass) email when that email is being sent to more than one customer. Any mass communication will have this link automatically applied.

It is important to have the Unsubscribe Link on mass (marketing) emails so that customers are choosing to Unsubscribe rather than mark your emails as Spam. 

Important note: When viewing an Email Template, you will not see the link appear within the template. But as demonstrated above, it will be in the email for the customer. 

If a customer clicks on the unsubscribe link, a tag will be added to that customer's profile. We recommend to leave this tag, otherwise you may be at risk for the customer to mark the email as Spam rather than Unsubscribe in the future.

NOTE: Customers will not have the Unsubscribe Link option on any transactional emails such as Invoices or Estimates.